Chevy Silverado and GMC Sierra Real World MPG Numbers



  • coontie57coontie57 Member Posts: 128
    I now have 10,000 miles and just got back from Florida and I was pulling my 12000 lb camper... When I was in FL and driving 55mph I got 11 mpg... then on the interstate at 65-70mph it dropped to 10.4ish..

    I must have had it FULL because it was slower coming up Saluda Mtn... just 56 mph today... and screaming..

    Diesel in FL was $2.69+..... in Spartanburg $2.53 and in Fairview, NC $2.80... PHOOOEY I saw it on I 95 at $2.51 in SC..
  • farmertimfarmertim Member Posts: 2
    Bought my truck on friday, dealer filled it up, and i filled for the first time today. I logged 378 miles, put in 22.5 gallons for 16.8 mpg. This isnt too bad, but it was about 90% highway miles at 60-65 on flat iowa roads with little wind and no load in the box and nothing being towed. Hope this goes up when the engine gets broke in as my 2001 Dodge Cummins would regularly get 20-21 on tankfulls like that.
  • rman6rman6 Member Posts: 11
    I am looking at new 4x4 3/4 ton pickups. I've always been a ford man, but the features and price on the new silverados are more appealing than the new fords. My big question is what kind of mileage to expect with the 6.0 in a 3/4 ton 4x4. I don't need a diesel (don't tow much, just need extra payload). Everyone I know have fords, so I need some input.
  • geo9geo9 Member Posts: 735
    R.........You can expect poor mileage.

    I am currently on the hunt for a 07 GMT-900 2500 x-cab
    to replace my 04 6.0 2500 x-cab, auto 4:10s.

    I can get 12-14 city......17 highway.............

    I note the new body style 2500s offer 3:73 rear gears so
    possibly can expect 1 or 2 mpgs more.

    Nice trucks but thirsty !!!! Since I need a 2500 for
    snowplowing and heavy towing I have no other choice.
    IMO a diesel for $7000 MORE and the possible few more
    mpgs is not worth it............
  • coontie57coontie57 Member Posts: 128
    I had a 99 Ford diesel and my buddy had a 02 Chevy with the 6L engine. We pulled identical campers from GA/NC to Homer Alaska and home. I drove 14,400 miles and he a bit less. Going through the Yukon where the gas stations are limited we had to fill up at the same one --side beside. It was quite impressive how many more liters of gas he burned on the identical miles driven. Gas station to gas station etc. Incidentally GAS was more expensive in Canada than diesel.

    I understand that the 6L has gotten better.. hope so for your sake.

    On my Durmax diesel and Ford 7.3 diesel I get/got about 20 mpg with no load.
  • geo9geo9 Member Posts: 735
    So as you can see your gonna get a couple of mpgs more
    with a diesel than a 6.0 gasser..................

    But its gonna take a LOOOOONG time to make up that $7000
    difference on a every day commuter ride..........
  • coontie57coontie57 Member Posts: 128
    The diesel engine will go a long way before overhaul. If you plan on keeping one forever like me its worth thinking about. And you also have to think if you are actually pulling something or just driving and commuting. After the tornadoes in Central Florida this Feb a group from Hearts with Hands cane down delivering supplies and they drove 3 Ford 250's. All three were donated and had between 310 and 333 K on them... each.. nothing ever done to the engines.. Stick Shifts..

    I am not sure a 6L gas engine would go that far without engine work.. The diesels will probably go another 100K or better..

    The diesel is messy to fillup ,, it smells if you get it on your hands etc.

    Its just a personal decision.. the power and fuel efficiency is impressive with my new Chebby (as a friend calls it).
  • geo9geo9 Member Posts: 735
    Perhaps you should take a trip over to the truck
    forums here. Diesels have many expensive issues.
    Many owners call the Ford diesels "powerjokes" and
    post on and on about injector issues among other things.
    Not to mention the major expense of maintaining them.

    Also note the new Ford 6.0 diesel and torqueshift trans.
    issues posted around the net. Or the recent articles
    of Ford withholding millions from their diesel supplier
    over warranty issues...............

    Yea I suppose you could get 300k miles from one. But at
    what cost? Employ a inhouse mechanic by chance?
    Heck the toyoyo owners brag that they get 300k (sic)
    miles. Without ANY repairs of course ! LOL!!!!!!!!!

    For the average buyer a diesel is a poor choice........

    Now I could start on GMs diesels past and present.
    But why bother..You get my point.................
  • 00chevy150000chevy1500 Member Posts: 1
    The reason why your friend in the chevy had to fill up more often is because chevys have smaller fuel tanks than Fords
  • jerryterry22jerryterry22 Member Posts: 9
    I read on a blog that the '08 Duramax Diesel would get 25% more gas mileage. Anyone have information on this?
  • coontie57coontie57 Member Posts: 128
    Yes I know that. Ford 250 Diesel = 29 gallons... Chevy 2500 Duramax = 26 gallons.

    The other had a 6 L gas engine in his Chevy and his mpg was less than the diesel AND his tank was smaller so I let him lead the procession from one gas station to another. He quit and got more fuel sometimes when I didn't. When we BOTH went from one station to another his consumption was much greater ie, he bought more fuel / liters or gallons depending on where we were. We traveled together for about 3.5 months.
  • jklingel8jklingel8 Member Posts: 10
    Just picked up an '07 3500 4x4, turbo Duramax w/ Allison 6-spd, SRW. From Anchorage to Frb, 350 miles, rolling hills and some descent hills around Nenana, we got 20.5 mpg. Traveled mostly 60-65 mph. I was amazed that the rpm, 1600 at 65 mph, never changed on the uphills. My '93 F350 w/ a non-turbo 7.3 liter would have r'd way up and the after-burner kicked in many, many times. So far, so good.
  • rman6rman6 Member Posts: 11
    Why is everyone so high on the diesels? If you're towing a heavy trailer often, then maybe they make sense. But for standard driving and a little towing is the extra cost and noise worth it? Not to mention they're not as responsive as gas, and although they've come a long way, you still can't just jump in them and go. You've got to wait for the glowplugs, then the motor to warm up. I'm not buying a soccer mom pickup, but I'm not towing around a cat or an 8 horse trailer either. There's only been one response to the 6.0 motor. What kind of mileage does it get, and what is the overall quality of these chevy 3/4 tons? I'm a ford guy who's looking to cross over. All I know about Chevy is that they built a really poor diesel for a long time and the 350 was probably the greatest motor ever made. Plus they're about $3500 cheaper than the new fords.
  • coontie57coontie57 Member Posts: 128
    There are a lot of different stories on the Fords. I had a 1999 250 diesel (7.3L) and the engine was fine... but the tranny was a problem. No problems until 72.500 miles then the skids just fell out of the Ford. Two transmissions... and a clip on A fuel injector plug... I sold it at 109,000 miles. I liked the way it drove.. I liked the interior ... very good visibility... and personally I liked the seats.. plush cloth?? My wife and a friend have both had back surgery and neither could stand to ride in it... back aches.. I had no problems.

    The diesel Ford got 20 or a little better on the road by itself and a friend of mine with a 6L gas chevy 2500 model is good for about 13 or so.. I think the newer ones might do some better but still way off the 20mpg on the road that both the Ford and my new Chev get.

    As far as starting both... the Ford you had to wait on a bit... but not the chevy but its newer... perhaps the Ford is quicker to start now.. they are both much quiter now then in 99.. The noise INSIDE the pu just isn't a problem or issue.. With the new Chev I actually ground the starter last year when I first got it because I couldn't hear it running. I have not done it since..

    A friend and I pulled our 8-9K campers to Alaska two years ago beginning May 12th.... the difference in fuel mileage between the diesel and the gas PUs was truly something to see. Stop after Stop after stop he put in much more fuel and we HAD to use the same gas stations as that's all there is... about every 100 miles. Our two campers were the same weight... same model and make... Two trucks... a 99 Ford Diesel ... a 2002 Chevy 6L gas.. Between the two of us we drove about 28,000 miles on that trip just under 4 months and didn't have a single PU problem... either of us.. The 6L gas engine pulled the Canadian mtns and those in AK just fine... perhaps better than the 99 Ford. But it made it just fine.. Ford Motor Co didn't see fit to give me a transmission temp guage so when the Chevy would stop to cool down I did too. There were several times when the EGT got nearly too hot so I had to hold back on the throttle to keep the turbine from getting too hot.

    We both NOW own 06 Chevy Duramax Diesel PUs.. We both bought larger campers .. more weight... and they pull the weight just fine.. 12000 lbs perhaps for me..less for him... 11.5mpg is the best I have gotten so far on flat land in FL pulling the camper... 10.5 on the interstate with big hills or NC mtns. OnStar just sent me an email sayhing I have 11,050 miles on it now so its still not broken in yet. Pulling my 21 ft bass boat (200 hp) it gets about 15-16.5mpg..and that's about the best you could hope for with a 6L gas engine with nothing in tow or onboard...

    Inside the chevy the seats are nice ... leather... very comftrable and the wife's back doesn't hurt... The XM radio is neat and the ONSTAR is just there till July .. I have never had heated seats before and that was a nice surprise this winter.

    Hope I answered your questions.

    I certainly don't have anything against Ford... I liked mine... and would still own it but the tranny deal was expensive and based on my experience I thought I could expect more trouble.. Ford did nothing to help me with this by the way except to take my $2850 for the first one... the second one was under warranty. Ford Motor Co and the local dealer played the good cop : bad cop deal to the max.. It was nearly funny with each pointing to the other..

    Something to also consider is the problem Ford is having NOW with their diesel engine manufacturer... I hear they are being sued by them.. or the other way around.. The two are not happy campers right now anyway. Can't remember what the problem was.. tardiness in production or something..

    I don't know what the gross towing capacity of the 6 L engine is but it used to be around 10,000,,, the 06 Chev diesel is/was 15,500 lbs as I recall. I was told early in life to not operate equipment/machinery near the capacity of the unit but somewhere within the middle range of the equpment... WELL that's what I was told anyway so that's partly why I like the diesel.. I am several thousand pounds under what it is listed as its capacity to haul.
  • rman6rman6 Member Posts: 11
  • kipkkipk Member Posts: 1,576

    Got some questions, hope you guys and gals have some answers! :confuse:

    Is there any type of indicator, such as a light, to let the driver know if the 5.3 is in 4 cylinder or 8 cylinder mode?

    Does the engine switch to 4 cylinder mode only at "LIGHT" cruising applications, or will it also use 4 cyl when idling or driving around local and back roads with a very light foot?

    Is there a "Real Time MPG" display as well as the "Average Mileage" one?

    If so, are the above in a particular package or trim level?

  • nascar57nascar57 Member Posts: 47
    Yes on the 07 Chev's there is a display that instantly reads out V8 Mode or V4 Mode, this is displayed on the screen the same time as the instantaneous mileage is shown. There is another screen that shows overall average mileage. As far as I have experienced with my pickup, if you make your foot a little bit lighter the V4 will in fact help you out with overall mileage. If you can keep the cruising speed under 70 mph, it will work but once the pickup gets over 70, I rarely see mine switch into V4. As far as I know, this is available on all of the Silverado's, no special package needed, mine is an LT1 and every pickup I have seen has it on. They are a dream to drive. One other thing for people reading this, there is a new fuel additive that has been stirring up excitement here in the heartland. It is a product made in Minnesota and has been delivering a 10-15% minimum increase in gas mileage. I have friends that have used it, went from 17 in their pickups to 18.5-19 automatically. It is called CA40G, there is a web site you all should visit This stuff is pretty amazing from what I've heard, I have a gallon on order and will report back. It works with any fuel (Gas, Diesel, E85) Would really help if everyone instantly got a 15% reduction in consumption.
  • bkerchakbkerchak Member Posts: 9
    Just purchased a 07 Silverado Ext Cab with 4.8 V8 and 3.23 gear ratio that is rated at 16 city and 20 highway. I drive a combo of city and highway miles each day. Can I expect the mileage as advertised on the sticker or will it be less ? What changes or add-ons to the truck would help improve or maintain the 16/20 numbers ? Thanks for the feedback !
  • oakradoakrad Member Posts: 2
    What are you getting for fuel mileage from your 2007 Chevy Silverado? I have around 350 miles on mine and the obc says it is averaging around 13.9. I have the 5.3L with 3.73 rear end and 4wd.
  • oakradoakrad Member Posts: 2
  • lionclawzlionclawz Member Posts: 12
    I have the 5.3, 2x4 and I avg 19.2 hwy, 16.9 city.
    Xtended cab LTZ - currently have little over 4000 mi.
  • bkerchakbkerchak Member Posts: 9
    I have an 07 4.8 4x2 with 3.23 rear end and I recently got 15 mpg on my first tank full of 87 octane doing city driving with the a/c second and third tanks were from a road trip to my cabin that is 300 miles each way of strictly highway driving and I averaged 19 mpg......not bad for a brand new engine that is just getting broken in......I would say that the sticker mpg of 16/20 are true if you stay at 65 and don't mash the pedal....all in all a great truck with good mileage that you can load up with all of your gear and the kids......
  • dwyerchevy07dwyerchevy07 Member Posts: 15
    I have a 5.3 4x2 3.73 (whichever ratio) 245 r17 tires and have almost 7k miles. I would think GM could do better for us who do not want 4wd to be able to get a min of 22 mpg. That truly is not too much to ask for a consumer who pays 30k for a truck. Yes, I know it is a truck but this technolgy we have today can do better. I also have the flex fuel option......E85 what a savings. I can buy gas at $3.05 in Michigan for 87 O and then buy E85 at $2.85....The saving well it is not a savings if you do the math. On a full tank of gas you lose over 60 miles per tank. That is about 4 gallons of gas. If you bought 87 O you would have went further...I know, I know, you save the environment...If you just bought E85 all year per tank you would lose $7.00 per tank. If you fill up once every week it would cost you an extra $364 a year. That is just about a truck payment. The consumer is always paying...we pay for the green of the environment and the vehicle....where does the manufacturer come in?????
    Frustrated on the gas situation.
  • nascar57nascar57 Member Posts: 47
    Yes, Ethanol does drop the mileage that you get. I live up in North Dakota and here E85 is selling for $2.54 and regular 87 Octane gas is at $3.09. With that spread you are a little better off running the ethanol. I have figured that on my 07 silverado I need ethanol to be at least $.50/gallon cheaper to make it even out. After that it works out, too bad that there isnt something that can be added to ethanol to bump the energy content.
  • bkerchakbkerchak Member Posts: 9
    Just paid $2.57 a gallon for 87 octane and prices should continue to drop until hurricane Dean hits land and then the refineries will say that there is another shortage.... with 1500 miles on my 07 4x2 with 3.23 ratio and the 4.8 v-8....I am getting almost 17 city and right around 21 highway....the same mileage that I got with my 92 Sonoma with the 4.3 v-6....I was told at he dealership that I should use Shell gasoline because they still put detergents in their fuels....If you don't use Shell they told us to add a fuel injector cleaner to the tank.....any thoughts on this ?
  • zeeboyzeeboy Member Posts: 25
    I've been searching for 4.8l/3.23 mileage and it seems like a few years ago seeing 17-20 real world mpg (mixed) was the norm.

    Now the NBS seems to get 13-16 mpg?

    What changed on the regular cab to drop the mileage? I'm aware the new EPA ratings changed, but again I'm looking at owner's report mpg.
  • olz442olz442 Member Posts: 2
    Getting the rated 18 city 22 highway with my Canyon, I was looking forward to getting similar numbers with a 2007 V8 Sierra thanks to the "advertised" active fuel management. So, since no one locally had a regular cab 4x4, I just drove 900 miles round trip to take advantage of the current rebate to "buy" my new Sierra.

    After getting there, the wife and I naturally went for a long test drive and I placed the dash display in AFM readout mode. Once the vehicle got past about 62 MPH, AFM never engaged once. Never leaving V8 mode, the instantaneous mileage varied from 13-19mpg with the vehicle on cruise control about 68mph. Now, if you drop below about 62MPH, then the AFM would engage and you would see a noticeable instantaneous mpg difference when it would enter V4.

    Question: How many people cruise down the highway below 62mph? :confuse:

    The sales person called his GM certified tech who responded by saying especially the 4x4s require all 8 cylinders above about that speed. Sadly, I drove back home with my Canyon but at least I learned of this during the test drive instead of after the purchase. I personally find this to be false or certainly misleading advertising. My '99 Sierra 5.3 V8 would get 16 city 20 highway without AFM. The 2007 ranging between 13 and 19 mpg on cruise control at 68mph, there's no way it's ever going to get 20 highway without a BIG asterisk *Below 62mph only. And this was just a regular cab version that's 600 pounds lighter than the extended cab and 700 pounds lighter than the crew. I can't imagine what kind of mileage they're going to get.

    Any chance GM would refund my trip expenses :mad: ?

    Thought those of you in the market should keep this in mind so you don't learn the hard way. I've seen others on this forum and elsewhere complaining about horrible mileage and just attributed it to lead-foot syndrome. I think they're just unfortunately experiencing in ownership what I saw during my test drive. When you're on cruise control, it's hard to blame your right foot. :(
  • trammell52trammell52 Member Posts: 1
    Ok, i have a 99 silverado ext cab 5.3 v8 4x4 and i get 16 highway and 10-a2 city. is that cuz im in highschool and drive 2 hard on the pedal?
  • harrybackmanharrybackman Member Posts: 2
    First of all, that's not true. I admit, over 75, it hardly ever kicks in. my new 07, purchased 3 weeks ago went on a 200 mile trip last weekend at 65, I was in V4 mode for 50% of the trip getting 22ish mpg. this is a 4x4 quad cab Z71 too. honestly, the biggest problem I have with milage is that i can't keep my foot away from those ponies.
  • bobw1bobw1 Member Posts: 19
    I am looking at a 2008 4x2 Silverado with the 5.3 engine. Should I get the iron block version or the flex fuel one? Will there be a difference in MPG or engine life or performance? Thanks...
  • olz442olz442 Member Posts: 2
    Though I'm thrilled you're apparently getting yours to actually go into V4 mode above 62, saying what I said is a lie is completely irresponsible. I drove 900 miles round trip to buy a new Sierra based on believing that AFM worked as advertised. The fact is that both going out and coming back on a LONG test drive with cruise control set to 68MPH, the truck never once entered V4 mode and I was getting instantaneous mileage between 13-19. You can't blame a lead foot when the cruise is set to 68 and you can't blame hills or the wind when it does it both directions. As I backed the cruise control down, when I would hit about 62MPH the truck would start to very intermittently go in and out of V4 and below 60 would go in and out frequently. That IS what happened. Period. What possible motive would I have to lie? That is after all the reason the new Sierra remained on the lot and the wife and I returned home in our Canyon. I thought others should know for those that think believable gas mileage is as important part of a new vehicle purchase as I do and maybe just maybe this technology has a few holes in it yet since others are complaining about horrible mileage too. I'll keep driving my Canyon in the meantime that actually hits and sometimes exceeds its MPG rating. Just got 23.5 on a trip to/from Colorado in it @70MPH and it's only rated at 22 HW.
  • 1offroader1offroader Member Posts: 208
    I am very impressed with the mpg on my 2007 4x4 crew cab z71 w/6.0 L engine. On a 350 mi. trip shortly after I bought the truck I got 18.2 mpg overall. This is before the engine was even broken in. On another note the on-board computer is very accurate. It showed 18.2, and I calculated 18.2 based on my fill-up.

    The truck frequently goes into afm mode below 70 mph, and occasionally between 70-75 mph. 74-75 mph seems to be the cutoff where the afm won't engage any more. I think it would easily meet (or exceed) the 19 mpg highway rating if I stayed at 65. BTW my trip was mostly in cruise control. That is key to getting good mpg. The trip also included about 10% mountain driving, but it is interstate thru those mtns. and the speeds were about 70 mph.

    In lousy stop-n-go Los Angeles traffic I get 14-15, which is as good as I can expect.

    AFM really works. As long as it is reliable, I am sold on it.

    I recently bought a pop-up trailer, approx. 2400 lbs. empty. I am curious what my mpg will be while towing. Will post when I have some data.

  • summitx02summitx02 Member Posts: 2
    1offroader, I'm getting good results too - I got an 07 Crew Cab MAX with 4:10 gearing, but I lifted it 3" and put on 33"s so I'm at about 3.85 effective ratio. Still, I got 17 mpg on a recent 600 mile trip which included a lot of "hammer time" passing RV's, mountain passes, hills, etc. I think I could have squeaked out 18 if I had been gentle. I'm getting about 14-15 in town easy driving.

    The bottom line is that there will always be some flat driving, downhill time, tail winds, etc where the AFM will engage and save fuel. I've actually seen it engage while pulling my 5000# Camper. There will also be times when you'll never see AFM engage - High speed highway driving, hot day - AC running all the time, head wind etc. Still, I'm sold on the technology.

    One potential problem is that the system does not rotate the cylinders that it disengages... i.e. the same 4 cylinders always turn off. Over time, will the uneven wear cause problems? With the tight tolerances and better materials used in these new engines, it may never be an issue, but my instincts lead me to believe that it could be.... Time will tell
  • 1offroader1offroader Member Posts: 208

    The issue of uneven cylinder wear should not be a problem. The pistons in those cylinders are still moving up and down - they have to, they're connected to the crank shaft. They just aren't drawing in fuel and firing because the valves are de-activated. I wouldn't worry about uneven wear, that's not going to be a problem IMO.

  • summitx02summitx02 Member Posts: 2
    You're probably right... I was thinking more in terms of uneven carbon depositing on the valves, seats, injectors etc. Still, things are made so tightly today that it's probably not an issue at all. I love my new Silverado!

  • bkerchakbkerchak Member Posts: 9
    I am thinking about putting a tonneau cover on my 07 new body style silverado ext cab. I am interested in a tri-fold but I am worried that the black plastic on the tailgate will interfere with the cover. Does anyone have any suggestions on types of covers or if this would be a problem. Thanks for the info.
  • phishyphishy Member Posts: 1
    If your getting lousy mpg and your buddy is not check to see which 5.3 you have? The aluminum block will get the lower millage than the cast iron block in my experience.
    My aluminum block with 310 hp gets average of 14.1 while my cast iron block 290hp will get 18mpg average and up to 21 mpg on the highway at 70 mph.
  • z15z15 Member Posts: 2
    I have an 08 Sierra 4x4 SLT Z71 E-Cab iron block 5.3

    I have seen mine go into 4 cyl mode about 65 mph while on cruise control. If you are not on cruise control any pressure on the pedal will not allow it the select the V4 mode. If the rpm goes up 1 it will kick into V8.

    About 5,000 mile on my truck. I was avg 18.3 mph till the winter weather hit and its dropped to about 17.6 but I have it in AUTO 4x4 mode all the time, snowing for 2 weeks straight and roads are mostly snow covered or slippery.

    A recent 500 miles trip I average 19.7 mpg on relatively flat county on cruise control at 65mph. Coming back I was carrying about 700 lbs of cargo. I also changed all the lubricants in my truck to synthetic, the engine, both axles and the transmission.
  • asylum575asylum575 Member Posts: 72
    I'm in the market for a new Sierra/Silverado. I currently have a 06 1500HD Crew 2WD. Happy with the power, but getting 11MPG. Would like to get 4WD and improve the MPG from the 11. The 1500 with 5.3/3.73 with AFM would probably fit most of my needs. However, there are a few times I probably would be better off with a 3/4 or one ton. Question is what are you guys getting with the 6.0 and new 6 spd in the HD. As stated above, the 5.3 would probably fit the needs, but if the current 6.0 with the 6 spd is getting over 15 regularly, I'd prefer that setup. I see GM has the 6.0 with the AFM in the 1500 series. Is the AFM coming to 2500/3500 or is that just silly?
  • doc_holidaydoc_holiday Member Posts: 2
    Well, I have the 5.3 on my "new" chevy 1500 2wd extended cab that is supposed to have the AFM. Ive put 22,000 miles on it since memorial day and have yet to achieve anything better than 18-19 (19 on a good day) MPG. BTW, the sticker said 22 hiway.

    My question for those who know, is if you have the truck without the DIC buttons, how would you know if AFM is active or not? The book says there is a display regardless of whether you have the DIC buttons or not, but fails to mention how one would know.

    I drive many days from gas station to gas station only touching the brake pedal and ignition when I leave the first station, stopping at the next one. 60-65 mph, cruise on, all highway. I drove 948 miles this week and might have achieved 18 mpg if I rounded it up. I generally get about 400 - 420 miles per tank and my fill ups are between 22.5 - 24.5 gallons. My simple math tells me that if I were to get even 20mpg, I should go 440 miles on 22 gallons of gas.

    No, I dont see any indication that AFM even exists. The serial number says it has it, the sticker says it has it, but other than that, there is no indication that it exsists or if it does, that it functions. Ive even driven 2 tank fulls with the trailer button depressed only to find the same exact milage.

    I love the truck, dont get me wrong. It's not the most comfortable for 6 or 8 straight hours, but it's a truck. My question remains. How would one know when the engine goes to 4 cyl. My next question (assuming there is no way for joe truck owner to know) is how would the dealership test it? Can they hook a computer up to it and see it function, can they engage the EFI manually or however AFM works? How can they show me that it is doing what it says it is or for that matter, even show me that it's installed?

    18 is ok? Thats 20% off the sticker. What if your wife was in the grocery store, bought $100 worth of groceries, and the store constantly failed to load more than 80% of those groceries in her trunk? What if you bought an air conditioner rated at 16 SEER only to find out it was a 13 SEER? What if the fuel stations only delivered 80% of the fuel the pump said it did?

    All I want to know is... Is it there, and if so, does it work (show me). It's a shame a coworker who has the same truck except his is 4wd and he gets over 20 per gallon with the same monthly miles and same type of driving.
  • fueledupfueledup Member Posts: 64
    about ready to purchase an 08' silverado 1500 ltz extended cab 8 foot bed 4X2 with 3.43 rear end. truck is loaded including nav. msrp $36,915, selling price $32,500 + tags, tax, and title. with 0%-60month financing. is this a good price and can I expect mileage as advertized. any advise welcomed.
  • bkerchakbkerchak Member Posts: 9
    I have an 07 1500 extended cab work truck with 6 1/2 foot bed 4x2 with the 3.23 rear end and locking rear diff and the 4.8 was advertised at 16/20 and I get right around 14/19......I run 87 octane with a tonneau cover... I only have 9,400 miles on the engine so I hope the numbers will improve slightly....I am thinking of adding a K and N air filter to help improve mpg......not bad for a v-8 that puts out 295 horse power and a truck that has a curb weight of 5,400 pounds...
  • the_big_althe_big_al Member Posts: 1,079
    I'm a little late to the party but... I have a 4.3, albiet in an S-10 and I have gotten as high as 24 on the highway, but usually about 22. City driving is between 16-18, depending on how you drive. I would assume that for a full size which is much larger and more wieght than the S-10, the mileage numbers would be significantly lower...
  • xscoutxscout Member Posts: 141
    After looking at the EPA mileage estimates, it looks like a Ram 1500 3.7 with manual gets about the same mileage as a Chevy 1500 4.3 manual, Dakota 3.7 manual, and Ford Ranger 3.0 and 4.0 manual. Is this really accurate considering the size and weight differences between these trucks?
  • obyoneobyone Member Posts: 7,841
    Yeah the ranger sucks.
  • newton1835newton1835 Member Posts: 1
    I have an '07 Silverado 4X4 Z71 with the 6.0L engine, 3.73 locking diff and live in Colorado. I am able to consistently get between 18 and 21 mpg with a combination of hilly and mountainous driving. I couldn't be more happy with it. As for the AFM, I can't tell when the truck is running in V4 or V8 mode except to look at the readout on the dashboard. Driving across Nebraska I consistently average 20 mpg in the flat country. In the hilly midwest near the Great Lakes, I'm lucky to get 17 or 18 mpg. In all cases, I drive between 65 and 70 as the law allows. As for trailering ... get the 4:10 axle. I didn't and I'm very disappointed in both performance and mpg ... usually between 8 and 10 mpg.
  • cumminsdieselcumminsdiesel Member Posts: 2
    Currently 43,500 miles on the truck. Daily NJ driver. Average MPG since new is 19.7. Getting consistently above 20MPG in the warm months, and 18-19 in Jan-Feb.
  • dad00dad00 Member Posts: 3
    Hi all, I have just taken delivery of an 2005 Siverado 1500HD with 66,000 kilometers (40+ thousand miles). The fuel consumption is atrocious - 12mpg in imperial gallons. (6L & 3:73 diff). Someone told me to check the thermostat as if it opens to early, at to low a temperature, the transmission will never go into "final stage" or overdrive and the diff won't lock causing slipage and higher rpms and fuel consumption. I have never heard of this. Is it a possibility?
  • jrzdvljrzdvl Member Posts: 5
    I have an 07 Sierra 5.3 4X4 with the 3.73 rear. To the guy wondering about AFM, I can tell when mine is in 4 cyl by the sound. The exhaust make a slight fluttering sound in 4 cyl (flat and level road) compared to the steady sound of the 8. You have to pay attention though. Like some others, I was also getting over 19 in warmer weather but it has dropped down now to about 17. (about 9000 mi on truck) That 3.73 hurts but it was not opotional. One thing I would suggest is Mobile One. I switched to that oil at about 3000 and saw an immediate jump of about 1 mile per, provable because I keep track of every drop of gas that goes in. I have switched to K&N filters in other trucks and cars and never noticed a thing in normal driving. Keep the tire pressure up, though
  • galvannigalvanni Member Posts: 8
    I'm currently shopping for a used (maybe a few years old) Sierra or Silverado. Does anyone know what year the 5.3 was available in these trucks of the top of their head? Thanks.
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