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Chevy Silverado and GMC Sierra Duramax Fuel Mileage



  • stonegstoneg Posts: 47
    I put about 5 oz. in my 26 gallon tank, and I picked up about 1 mpg, but I just installed the Edge Juice programmer, and put in on level 3...picked up 1.7 mpg, and 75 HP!!! I was getting over 2 mpg better, but when you have an extra 75 HP, its hard not to use it. I spoke to the owner of a Diesel specialty shop, and he has never heard of using the Acetone, but is now researching it. He is also skeptical of using biodiesel, saying that nobody knows the long term effect on the engine. Any comments on biodiesel? Also, I think I found out why my mpg suck so bad, 4.10 gears, instead of the 3.73
  • I am a diesel mechanic for about ten years and the fleet company that I work for uses veg. oil mixed fuel in some of thier trucks since they got them, and those trucks have over three hundred thousand miles on them and still run like a top. the mixed diesel is similiar to biodiesel cause both use veg. oil. I know some guys that use biodiesel and the see no difference. But, as for the acetone thing I wouldn't recommend using it cause it has a lower flash point than diesel does and it will actually cause the motor to pre ignite causing misfires. Its on the same basis as putting gas in your diesel. cause gas has a lower flashpoint than diesel and will do the same thing.
  • stonegstoneg Posts: 47
    Yeah, I am a little nervous about adding it again.
    This past fill up, I added an additive by Stanadyne that I got from Shivers Diesel, and along with the Edge Juice programmer on level 1, I went from around 10 mpg to now almost 14. The exhaust is on order, and hopefully I will get another 2 mpg increase if you believe all the hype.
  • I drove the Dmax roughly 500 miles the first day. Trying to get it back home. I averaged about 17mpg mostly highway doing 75mph. The next day having to drive the last 100miles I decided to keep it around 1600rpm. That put my speed at around 63 in 6th gear. Trying to keep it in peak torque range. Averaged 22mpg freeway only. It seems to average about 15 mpg mixed. The 6th gear really helps with increasing the mpg.
  • I am following this article for break in.

    And on DMAX the has alot of info.
  • stonegstoneg Posts: 47
    so does the 3.73!!! The 4.10 in the '05 sure isn't helping.
  • Just curious if your mileage is calculated manually by you when you fill the truck or if you are reading off of the DIC. I have found that the DIC mileage is way off. I have an 2004.5 LLY motor in my GMC Sierra Crew Cab Short box. My lifetime mpg average at 15,000, calculated by me from fuel reciepts is 17.8, this was a mixture of highway and city. I just finished putting a predator programmer (fuel economy mode selected), MAC intake, and a Jardine 4" exhaust. Today I took the family to Chicago and back running 75mph the whole time and average 20.1mpg based off of actual miles traveled divided by the actual fill...the DIC showed 26.5mpg??? I am very pleased with 20mpg. I believe I can get up to 21mpg if I hold it at 65mph, or essentially keep the motor below 2000rpm which is where everyone on the forums states they get the best mileage. Glad to hear you have the Allison with the 6 speed.


  • stonegstoneg Posts: 47
    Sorry fellas, I mentioned before that I took my 05 CC D-Max to my dealer to recalibrate the speedometer for the 285.75.16's, and now I am beginning to wonder if they did anything at all. I recently installed the Edge Juice with Attitude, calibrated it for the 285.75's and there is a noticable difference in the speed. I am now thinking that I am actually getting better MPG than shown or hand calculated, because the truck is actually going further with each revolution than the computer is calibrated for. I guess the only way to find out for sure is to get on the open highway, reset the tripometer and take a look upon passing 100 mile markers. I'll bet the computer says I have traveled less than 100. (sure hope those DOT boys are accurate!!)
  • I am considering buying a new 2006 DMAX, 2500HD 4x4. What kind of everyday mileage are you getting city/hwy and is your DMAX a 4x4? I plan to use the DMAX to pull a camper but the majority of the time will just be for driving back and forth from work. Thanks.
  • Is it the new 360 HP / 650 lb-ft DMAX? I am also thinking about getting a 2006 2005HD 4x4 with DMAX. I was just building one on and saw a 360 HP DMAX as an option for 2006. I ruined a pair of perfectly good pants! :surprise: Dang! I guess the Torque wars are far from over. Dodge and Ford better step up to the Chevy, or Chevy will just keep eating them for breakfast. :)

  • stonegstoneg Posts: 47
    update....yes there is. If you are looking at adding the Edge with Attitude monitor to your 2500HD, and it has a sunroof, the overhead console mount on Ebay will not work for your truck. Also the black plastic one that says it fits all makes and emodels will NOT work if you have the sunroof option. You have 3 mounting options: Use the supplies mount, use a pillar mount, or what I did, drill a small hole in the smaller of the two lower consoles for the wire to go though, and sqeeze in. Its rare that people in the truck ever even ask, "hey what's that?" It just doesn't look like it has been added aftermarket. If you DONT have a sunroof, the overhead console mount with the two built in auxillary switches looks awesome.
  • stoneg if you don't mind me asking where did you purchase your aftermarket torsion keys at ?thanks
  • funny you should ask. today i had the exact problem you are talking about today. i also have an 05 duramax. could"nt get the rpm's above 2000 rpm's. you described my problem to a tee. it's on the back of a flat bed as i speak. will let you know what the problem is after it get's back from the dealer!!
  • the dealer finally figured out the problem. it was a clogged fuel filter!!! i have 16,000 mi and i can't believe it was clogged!!! and they wanted to charge me $180.00 to fix it. say's it wasn't under warrenty!!! say it's like an oil change. good thing i spent $49,000 on a chevy. might want to get your own from a parts store!!!!!!!!!!!!!
  • stonegstoneg Posts: 47
    at a place in Tallahassee, FL called MINCO
    If your nowhere near here, look on EBay, I've seen them there for, I think around $40-$60. After you change them out, you'll need to get your truck re-aligned. If you want to get that "cadilac" ride back after the torsion key install, switch your front shocks out to the Bilstien 5100 series. These shocks are longer to accomodate the 2.5 inch increase in height. I didn't do it at first, and the ride was pretty bad going over even a speed bump at low speeds. It seemed as though the truck would "top out" causing the truck to slam up and down. If you do it (highly recommended) go ahead and spend the extra $100.00 on the shocks. I have seen the shocks in accessory catelogs for less, but I had minco order and install these as well. I get lots of compliments at stop lights, gas stations, etc. for the way the truck sits level. Good Luck.
  • I have an '05 2500HD Crew 4x4 D-Max/Allison... I love this truck. I bought her new on May 1, and since then have put 18,750 miles on her. This truck is my daily commuter, not to mention I've towed everything from bobcats with a total load of 12k on the ball hitch to little pup trailers. I have found my normal unloaded mileage with my commuting around the DC area, has averaged 17-18.5 mpg's, on the highway unloaded I have found I get about the same but I'm holding 75mph.
    I have a K&N filter in mine, and haven't noticed a difference in the mileage or performance at all. One thing I noticed that did cause a change in my MPG's was source of the diesel I was using. I have found that getting my diesel from a quality supplier helped in my MPG's.
    I'm currently looking to level my truck and put 285's on her. I'm planning on using a kit from ORU ( and they sell the kit with the longer Bilstein 5100's for a little over $400. I'm also looking at putting in either a Banks Big Hoss kit, or an Edge Juice with Attitude monitor, with the appropriate opening up of airflow. Any one have any suggestions or stories about using either of these 2 particular products?
  • I have an 01 X-Tended Cab 4x4 with the Allison and D-MAx of course. I live in Iowa where winters are kinda cold. This is my first Diesel and I'm curious to what anybody else is using for engine oils out there. I can't afford Amsoil or Royal Purple, but any info would help. By the way, I get 19 mpg city/ 24 highway. Thanks
  • I have a friend with a 2004 ford f-250 with the Edge Juice system, air intake system and aftermarket 4" exhaust. It tore his truck up. He had to put a new tranny in it and just before he got rid of it the motor was running really poor. Ford wouldn't replace the tranny under warranty. Not a cheap tranny for him. Personally I would go with the Banks system and upgrade the tranny with a stouter torque converter or aftermarket perfomace tranny(ATS or BD) along with the other modifications. That's what I want to do to my truck(2004 2500hd duramax).
  • spademan

    I live in wyoming and winters here are pretty cold. It's not uncommon for the high temperature to be below zero. I run Shell synthetic rotella 5w-40 all year. But 10w-40 or 15w-40 should work all right. Make sure you get a diesel motor oil. And I always warm up my d-max for at least 15 min.
  • stonegstoneg Posts: 47
    Ive got the exact same truck, K&N filter (not the entire intake) already did the leveling kit, 5100's, 285/75/16 BF Goodrich AT TK KO's (had to still trim the front valence a little to keep from rubbing. I did the cat back Banks 4" Stainless Exhaust with the straight thru muffler and the 5" tip. I was having a hard time deciding which programmer to go with also. It was between the Banks or the Edge with attitude. I decided on the Edge for two reasons. (1) I liked the in cab monitor better, and (2)every single person with a D-Max that I met who did install a programmer went with the Edge. I have had absolutely no regrets. I also talked to a diesel specialist (Shivers Diesel)and the Edge was the one he recommended for the D-Max. You are getting some awesome mileage!! I bought mine about 3 months ago, and now have about 6,000 miles, but have NEVER seem mileage like that. Most of my driving is stop and go, but I did level kit 2 days after the purchase, and swap tires within 5 days. Maybe its the tires???(or my heavy foot) My city MPG averages 12.5
  • stonegstoneg Posts: 47
    Every aftermarket shop around here (including the Diesel Specialist) recommends the Superchips for the Powerstroke. My best friend and neighbor has the '04 F250 with the 6.0, 35" BF's, installed the Airade intake, Superchips programmer, and a 4" Exhaust, and loves it. He has had absolutely no problems, and he now has close to 55k on it.
  • stoneg

    On your Bilstien shocks what was the size of the shocks? How much of a bigger shock did you have to get? I only cranked my torsion bars. I was thinking of going with the Rancho rsx self adjusting shocks or bilstiens. And on the matter of the banks or juice I like the pda system that banks is got better the juice module. But they both sound really good. I just don't have the money to do it right now.
  • stonegstoneg Posts: 47
    I'm not sure what the size was on the 5100's, but they made all the difference in the ride. I never turned the torsion bars, I switched the torsion bar keys which lifted the front by 2.5 inches (level). The ride was really rough due to the stock shock not being long enough, so I had them switched out to the 5100's. Yeah, I saw the PDA version, but it made the kit very pricey, and where in the hell would you mount it to where you could actually use it? To me it is too big to mount (and keep everything stock looking), but the display to small. I mounted the Edge monitor in the small console in the dash, and rode my wife around at night with the thing all lit up, and after about a 25 minute ride I had to point it out to her!! Very clean stock look to it. Now before you say she is unobservent, she noticed the truck being level, and totally shocked me when she asked if I lifted the truck.
    Try Ebay for the programmer..I saved alot of $$$ there on it, and my Banks exhaust.
  • KCRamKCRam Mt. Arlington NJPosts: 3,516
    Even in sub-zero, 15 minutes to warm up a diesel really isn't helping the engine. Diesels will generate heat much faster when they're actually working, and that means moving the truck and going through the gears. Even sub-zero, my Cummins is put in gear after no more than 3-4 minutes unless I'm brushing off the snow... then the truck is driven as soon as I get back in the cab. I have full heat in just 5 minutes at highway speed.

    kcram - Pickups Host
  • We have diesel electric generators(catapillars) at work and if you don't let them warm up 15 minutes or so and then put a load on it will kill the motor or have big puffs of black smoke coming from the exhaust just barely chugging along. So I still believe in warming mine up more than 3-4 minutes.
  • Iam buying a 2006 LBZ crew cab 4x4 in 2 days. I could use some input! Should I be getting the 310 hp model because it is a whole lot cheaper (thousands) Or is this new Durmax the way to go. Is fuel mileage the same. Or should I be buying a gas Silverado Help!
  • Anybody I have talked to that has the big V8 is only getting in the mid teens for mpg empty. After they load them up it drops down to 10 or lower. I got the DMax for this reason and get 18 in town and almost 24 on the highway. It depends a lot on how you drive,
  • I will have to agree with Kcram on the warm up. Yea you don't want to start out full throttle blasting down the road but idling for 15minutes is a waste, it will never really warm it up in cold cold conditions. I usually startup and idle for around 5minutes or so then head down the road but going very easy starting out. Once you have driven a mile or two down the road it will warm up in a heartbeat. If you live in a colder area you might think about plugging in the block heater.

    2000 Dodge Ram2500 regular cab 4x2 with 5speed.

    25mpg hwy (A/C and 70mph)
    20mpg city (no A/C)
    17-19 City (With A/C)
    lowest mpg 16.4mpg pulling a 17ft. ski boat rural driving.
  • brycarbrycar Posts: 10
    I would get the one with the 360 hp i thinks it better than teh 310hp Engine, Duramax 6600 Turbo Diesel V8, (300 HP [223.8 kW] @ 3000 rpm, 520 lb.-ft. [702.0 N-m] @ 1600 rpm) (LLY) $5,310.00 Engine, Duramax 6600 Turbo Diesel V8, (360 HP [268.0 kW] @ 3200 rpm, 650 lb.-ft. [881.0 N-m] @ 1600 rpm) (LBZ)
  • stonegstoneg Posts: 47
    For what it's worth...I've got the '05 2500hd cc 4x4 310HP and don't pull anything and only get about 12.5 mpg city 15 hwy.
    As diesel prices are now higher that gas (even 93 octane!), if your not pulling anything or driving considerably high mileage don't bother with a diesel. I keep reading about people getting 20+ mpg, and I frankly just don't see it. I have added/tried EVERY possible aftermarket way (edge, 4" exhaust, intake, acetone, stanadyne, etc.)to improve mpg and some have helped me go from 9mpg city to 12.5, so hope its not to late, and you made the best decision for you.
  • I had been interested in the Duramax since it's conception in 1999. I know when it first came out, they said it would get around 28 miles per gallon. I agree with stoneg, that when they came out diesel was around $110 a gallon. I bought my first in 2001 and was getting 18 miles per gallon. When I bought a 35 fifth wheel trailer, I got around 12 miles per gallon. I purchased my newest one in 2003. I put a straight through muffler on it and pull and drive all the time. I do get 22 miles per gallon on the highway and 17 in town. I do like it and am very impressed with it. I have looked at the new 360 horse Duramaxes and they have the 6 speed Allison transmission which should make the truck get better gas mileage. I know that I will get one soon.
  • Can anybody tell me where to order some better looking door emblems? I've seen them around but can never catch anyone to ask them. They look more flashy than factory. Any info would be great!
  • :lemon: My father has a 2005 silverado with about 15k on it. It is a diesel and its a sweet truck. Recently he had a issue where his check engine light would come on and error code states something wrong with the fuel system. The truck would bog down and have no power. He brought it to the dealer about 6 times and they can't tell him whats wrong. So now he rides with a computer plugged into the jack all the time and when it happens he just resets the truck computer. Does anyone have any ideas what could be wrong. They did replace the fuel filter and things like that but still keeps happening.

  • tcoletcole Posts: 2
  • I dont know if it is the same problem, but the exact same symptoms. My fuel gelled up on me and the check engine light came on in my 2004 duramax. I was coming home from work and the motor had returned to normal by the time I got home(3 hours) and the check engine light was still on. The dealer plugged it in and the low fuel pressure rail came up. They cleared the code and I was on my way. Runs like a champ again.
  • Hey
    I have a 2003 DMAX 4x4 crew cab dually and was wondering if you run veggie oil on yours and if so how it is running and what you did. Any help would be apprecieated.

  • This happened to my company '05 2500 between 20-30,000 miles. Finally found out it was the fuel flow regulator valve or sensor. The Dealer replaced the left side fuel rail and it hasn't happened since. The symptom is just as you described and most techs said it was a clogged fuel filter, but I finally found one that looked deeper into the issue.
  • p100p100 Posts: 1,116
    To pull 25k pounds on a regular basis you need a commercial truck, IMO. The new Duramax 360 HP engine in a dually pickup would handle it, but the truck itself is simply not large enough for such large trailer loads. I would not try to go over 15K pounds trailer weight with one of those. My $0.02
  • ezshift5ezshift5 West coastPosts: 858

    2000 Dodge Ram2500 regular cab 4x2 with 5speed.

    25mpg hwy (A/C and 70mph)
    20mpg city (no A/C)
    17-19 City (With A/C)
    lowest mpg 16.4mpg pulling a 17ft. ski boat rural driving.

    ...don't know what Cummins tachs at 70.......

    ..but at 55-60 without a/c......your fuel use (non-use actually) would probably not be readily believed....

    best, ez...
  • Has anyone tried the magic pills (Bio-Performance) for increasing your fuel mileage by 35 to 50%? If anyone has any experience with this product, please reply. I am very curious if this will really work? Here is the website for this:
  • Pulled 6500lbs in the form of a classic truck across NC the other month with my dads 2005 Chevy 2500 HD Crew Cab 4x4. Averaged 16.3mpg!!! That is better than most folks say they get running clean with a Dodge or ford. That Duramax with the Allison 1000 tranny is a perfect marrage for pulling. We use the truck for pulling farm trailers and pulling maybe 4000lbs it averages about 18mpg! Running Clean at 55mph I have hit the 21mpg mark. Amazing for a truck 6000lbs. I dunno as I beleive that that Dodge gets 25 mpg at 70mph with the ac on. The Duramax won't so that makes me suspect about Cummins age old desighn.
  • I have 3500 miles on this regular cab that has the Allison. I am a very conservative driver and have always gotten better than average mpg. It runs great but its getting the same mileage as my old 454 but the fuel is higher priced.
  • donwydonwy Posts: 2
    I have a 2005 crew cab 3/4 ton HD with the Duramax and about 2400 miles on it. Living in Northern Canada, the temperature is cold this time of year but I am still getting 13.8 mpg (US gal.)on winter fuel when doing all city driving in heavy traffic and about 17 mpg on the highway with two passengers and no load. Sounds like you have a problem.
  • I would hope people realize the clever marketing behind all of those outrageous claims of increased fuel mileage from these fuel additives.

    The last two links were two products that claim alot. Both sites spend as much time trying to get you to sell their product than use it. Come on people...putting a giant pill in your gas tank. Are you kidding me! The last one is talking about CNBC World Business Review with Alexander Haig. It is well known that production costs for WBR are paid for by the company that wants there product on air. Please save your money.

    You want to save down the freeway at 55mph and don't show off your trucks power at every intersection.

    Smoke and Mirrors...Smoke and Mirrors. ;)
  • KCRamKCRam Mt. Arlington NJPosts: 3,516
    Please do not post phone numbers or any other contact information... this is against the rules, and opens you up for abuse as well.

    kcram - Pickups Host
  • Help!
    @003 chevy 1 ton diesel dually - inside edge of inboard back tires are getting scalloped edge. ALL other tires are fine!

    Whats going on?!!!!
  • KCRamKCRam Mt. Arlington NJPosts: 3,516
    You want to post that question in the Chevy Silverado: Problems & Solutions discussion for better response.

    kcram - Pickups Host
  • I have a 2005 2500HD with the duramax. I have 11000 miles on the engine. I recently pulled a 3000lb equipment trailer 440 miles and my mileage dropped to 9 mpg. The local dealer told me it could be the fuel filter. I need some help!
  • fredk2fredk2 Posts: 4
    Did you look at your air filter gauge. Try a different fuel station.
  • fredk2fredk2 Posts: 4
    I have just purchased a gmc extra cab 6ft bed 4x4 with the duramax and the auto trans 6 speed. and I check all fuel mpg on every truck I drive soon as I get fuel reset trip this truck gets 15.80 mpg I was told by people I see with same Truck they got around 20 mpg have to see if it will get better it only has 360mi right now and maybe has winter fuel. If anyone get better mpg please post and let us no spec. 2wheel or 4x4 3500 or 2500 thanks.
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