Just an update on my truck mileage. I have a '98 GMC Sierra K1500 Z71 SLE with 3.73 rearend, 5.7L engine and auto trans. I now have slightly over 9400 miles on it so far. For the first time now I've gotten over 21 mpg on ~85% highway driving, and this is the 5th time I've gotten over 20. My last four fill-ups are below:
My truck actually has better range between fill-ups than my wife's Buick LeSabre. Of course it also has a 25 gallon tank to her 17 gallon tank, but still... I'm impressed with GM trucks! I can only guess as the '99's and 00's start breaking in, people will be reporting 22's and 23's since their engines are more efficient. -powerisfun
The last fill-up on my 99 F-250 SD extended cab 4x4 long bed w/tonneau 7.3 power stroke diesel, auto trans, 3.73 rear end was 17.74 mpg. Truck now has 1900 miles on it. No problems, no complaints so far.
I have a 95 silverado-xcab, 350. It just turned 180,000, put an a/c on it 1 year ago and a water pump on it 2 weeks ago, no other problems except everything is starting to act up. Switch's, buzzers, wipers, etc. I have used Royal Purple Oil since it had 20k on it. I think I got my money out of it. Owe, 15 mpg everywhere. Am wanting to get a 250 sd cc v-10, may be a gas hog but sure is a good looking truck, I hope I get one of those that gets 16.9 mpg. I have a 30 foot pontoon boat so the length and weight will help it tow straight. 6-7 mpg towing the pontoon in the chevy. Thanks for all the info everyone
I purchased a 99 f250 Sc LB 5.4L 4:10 rear end in Dec of 98. Gas mileage is terrible. 10-11 mpg city highway. Just not enough engine for the truck.Had a gooseneck trailer towing on Fri. Got 9.1 mpg on a 250 mile road trip. When I got back to town I went to my Dealer to order a 2000 with a V-10. I don't recommend the 5.4 under no circumstance. I think there will be more power and better mpg with the V-10.Any suggestions.
ANYONE EXPERIENCING PROBLEMS WITH DRIVE SHAFT WHILE SITTING IDLE WITH BRAKES APPLIED AND VEHICLE FEEL AS THOUGH IT HAS BEEN REAR ENDED AND LAUNCHS FORWARD. ANYONE HEARD OF A RECALL ON 92 EXTENDED CABS FOR THIS PROBLEM? IF SO, WHAT WAS THE PROBLEM. I OWN A 93 EXT. CAB CHEVY 1500.
Thanks jeffi for the input yes my dealer said that the 5.4 was not enough motor for the 250 but I am just going for the 150 as I am going to use it as a car with just light weight hauling once in a while. I like the dodge looks the best but the seat is so much better in the ford is the main reason I am looking at that. I drove a 99 chev silverado and it had horrable road noise so I am scouting to try to get the best I can.
The mpg figures you quoted are close to what I get with the V-10 and 4.30, and I get the benefit of the extra power. If you get the 3.73 axle ratio with the V-10, your mpg should improve quite a bit. I don't think you will be disappointed, especially with the increased V-10 power for the 2000 model.
I read an article recentle about the best ways to reduce truck drag, and therefore increase fuel economy. There were various options tested, largely concentrating on air flow after the air became turbulent (behind the cab).
Anyway to cut a long story short they reckon that a tonneau cover reduced drag by between 20 & 30%. This all came down to the fact that the air is prevented from entering the truck bed and becoming even more turbulent. Not sure if I believe the figures, but this must translate into a significant increase in economy.
Geez, you don't half like making me work don't you. I was fairly convinved that I read it on the web, but I couldn't remember where. Anyway, after an exhaustive search I found it.
Thanks for the website address. Sorry for making you work so hard, though. I'm going to go read it now. I agree 12% is a significant reduction. I have a hard tonneau cover on my truck and I'm really happy with the mileage I'm getting (I have a '98 GMC Sierra x-cab Z71, 5.7L, 3.73 rear, 9900 miles, and I'm averaging over 20.5 on my last 4 tankfuls).
I dont know how much better my MPG's were with my tail gate down but Ive been doing it now for 175,000 miles on the same truck. It had a 2.5" lift kit and 33" inch tires on it so wind drag was very noticeable. Occasionally I would accidentally leave the tail gate up and would notice rite off the extra drag. The drag becomes noticeable at hywy speeds. It really does make a difference with it down.
Hi rudy, If you read the website listed in the above response by andy_jordan, it shows research into wind drag on pickups. According to them, leaving the tailgate down reduces drag by something like 3%. Oddly enough, removing the tailgate or installing one of those nets in place of the tailgate disrupts the flow and causes an actual increase in the drag. A tonneau cover decreases drag by 11.8%. -Tim (powerisfun)
A good friend of mine worked was an aero-engineer for the Navistar truck division. His boss had also worked for Ford. He said they ran many tests that showed leaving the tail-gate UP produced less drag. The reason: With closed tailgate, the bed becomes a "stagnant area", that has no effect on the truck dynamics. The area flows over the cab, over the top of the bed, and the laminar separation point occurs at the tailgate. This means your "pressure-drag" occurs on the tailgate.
With the taigate down, the separation point occurs at the top of the cab. This means the pressure drag occurs over the the back window, and the front of the bed, which is a larger area than just the tailgate.
Pressure drag is called such because the pressure on the back of the vehicle is lower than that on the front of the vehicle (because of the more turbulent flow, from separation).
Now, that study was done on Ford production trucks, no aftermarket. Lift kits, tires, toolboxes, etc, can certainly change things.
I enjoyed the study on Air Drag, thank you Andy. I was considering some kind of flow-through tailgate, now I won't bother and will look into a bed cover. I drive a '99 Dodge QC 4x4,AT, 5.9L with the 3.55 axle ratio and 11300 miles. I have kept track of the mileage on every fillup, the worst was 13mpg towing a 2000 lb tent trailer (I think the gas was oxygenated because I got the same lousy mpg when I filled up at that same station again and I was able to get 15.8mpg on the same trip from other fillups). The best mpg has been 16.8 twice, living in AZ these figures are always with the AC on. These figures are with the tailgate up and a K&N filter, I will be putting the paper filter back in for a run or two on my 300 mile test route in the next couple of months as I want to see if it makes any difference now with the engine a little more broken in (the K&N filter went in at 7000 miles and I don't have mpg on that route for the paper filter). I will post the results.
Someone asked about the 360 gas mileage. I have a '96 supercab,360 auto with the 3.55 gears and trailer towing pkg and limited slip rear axle. I get 11-12 around town (few stoplights,little town} and about 14 to 15 on the hiway with some town thrown in. Straight hiway [gas station to gas station} on a trip across New mexico and Arizona cruising at 75-80m.p.h. got me 17.3 to 17.4 for 4 tanks in a row. I really feel that the new trucks ought to get alot better mileage than they do. I also have a 1951 Ford F-3 H.D. 3/4 ton p.u. with 4.86 rear gears and the original 4-spd, it now has a 289 under the hood and it gets about 10-11 mpg around town, with the original v-8 flathead ,it got 9 in town and 11 to 13 on the highway depending on how much weight it was pulling. Speed has a lot to do with gas mileage also, a 50 m.p.h. wind has a force of around 12 lbs.per sq. foot, while a 100 m.p.h. wind has a force of 50 lbs. per sq. foot. Double your speed and the wind force against the front of your vehicle will quadruple, thus requiring more gas.
Those are impressive numbers for a 360. From the info I've heard from other owners and friends who have owned various makes and models of vehicles, when it comes to gas engines, the Chevys seemed to get the best mpg. Ford and Dodge were 1-2mpg behind.
My 92 F-250HD 4x4 with the 351 and 3.55 only got 14-15 on the hwy. That's about what the new Ford V-10 with the 3.73 gets and the new V-10 has a lot more power. Same mpg with significantly more power. I'd consider that an improvement. Maybe someday they will make a gas engine that will get close to 20mpg and can effectively move a 7,000 pound truck, but for now, they call it a diesel.
We have a 99 Silverado, 2wd, ext.cab SB, 5.3 engine, 3.7 locking dif, Stockland canopy, with under 5000 miles on it. Just got back from first road trip, Seattle-Davis CA-Seattle, about 2000 miles. Average was 18.8; 3 out of 5 fill-ups we got over 19 mpg, one tankful 18 point-something going thru Siskyou Pass, and 17 point-something running around Davis-Sacramento. Mileage is gradually improving, and the rig is VERY comfy on the freeway.
I have a 99 Silverado 4WD Z71 with the 5.3 and have about 10.5K miles on it now. The majority of my driving is in town with occasional road trips. Overall average now is around 15.8, which is 1 tenth less than I had with a older model 4.3 V6 in a K1500 several years ago (90-91). Over the road with the 5.3 I have been seeing any where from 17.8 to 22.9MPG. I know of none of my friends with Ford, Dodges or Tundra's that are getting close to what my friends and I are getting with the GM's.
I have a 97 F-150 extended cab 4x4 ORP 3.55 gears 5.4 and I usually average between 17-18 mpg. I have gotten 18.5 a few times. If I took it alittle easier I could break 19 easy.
A question for you What was your milage when you first got your rig? I have a 2000 silverado LS 5.3 /3.73 rear/auto and I have 1800 miles on it now and all I can get is 17.1 and that is all highway if I do any in town or short running I get 16.1 I sure will be happy when it comes up some, I am going to put a canopy on it next weekend and that is supposed to help we will see.
Has anyone with a 1999 or 2000 Chevy or GMC pick'em up with 5.3L with high capacity air cleaner (option code K47) tried a K&N filter. Assuming there is one for that engine. If so, results please as well as any impact on the computer measuring a larger volume of air. Thanks.
I think we got 16.5 for the first tankful or two, at which point we put a canopy on. Around town mileage still about the same. 5500 miles or so on now.
what is the milage differance between a 5.4 and 6.8 in a 2wd crewcab with 3.73 and auto trans? I am considering a new pickup to pull a 5,000 lb. 5th wheel. I have a 96 ford powerstroke 4x4 auto with 4.10's for my big stock trailer. it gets 15-17 on the highway at 75.
The best mileage I have ever gotten is just over 20. That's in a 5.4 short wide, non 4X4, non SC, auto, 3.55's doing about 75-80 on the interstate. If I lay it out on a highway it will get this everytime. Gunning around town I get 14-16. Later.
I have read through 402 posts and 95% of of the commentary is related to the Ford SD. Very few comments are related to the Dodge V10. Does that mean there are few Dodge V10's around compared to Ford or are the Dodge owners just reluctant to talk about it? I have a Dodge 1998 1500 now with the 360 but need to upgrade to a 2500 to tow a 11000# GVWR 5th wheel I am buying. I like the looks of the Dodge better but am concerned with the reported poor gas mileage. I would consider a diesel but I live in Minnesota and have heard that the diesel engine isn't suitable for cold climates. Any comments? Are there any more Dodge V10 owners out there that have gotten better than 10 mpg? Thanks
There's a topic devoted to the Dodge V10 so try doing a topic search on "V10" and you should get it. There's also a topic on the gas V10 verses the diesel. Good luck whatever you decide. -powerisfun
my 1999 f250 sd extended cab v10 has aprox 1300 mi on it, i'am averageing aprox 11.5 mpg on all around driving,has anyone upgraded to the k&n performance kit? has it improved the mpg? or the power?
One thing I meant to tell you was that your mileage will probably improve with time. When I first got my GMC ('98 Sierra K1500, 4x4, ext-cab, Z71 off-road, 5.7L engine, 4sp auto trans., and 3.73 axles), I was averaging 16 mpg for the first 3000 miles, but now with 11,900 miles I'm averaging 20.6 mpg (mostly highway). That's with a hard tonneau cover (which I highly recommend for good mileage), but I installed that immediately after buying the truck (less than 200 miles). Good luck! -powerisfun
My silverado with the 5.3,3.42 has 1200 miles and the best mileage I have shown is 13.6 mpg. Should this get better after a few more miles or is this it? The engine also hesitates sometimes when I first depress accelerator. Maybe I should have it checked on the computer? any suggestions?
My silverado with the 5.3,3.42 has 1200 miles and the best mileage I have shown is 13.6 mpg. Should this get better after a few more miles or is this it? The engine also hesitates sometimes when I first depress accelerator. Maybe I should have it checked on the computer? any suggestions?
That mileage seems quite low compared to what others are reporting. Unless that is mostly city miles in heavy stop&go traffic and you are very heavy on the pedal between stops, I'd say you might have a problem. Most people are reporting about 15-17 in city and 19-21 on the highway. The hesitation also doesn't sound right. My '98 has no hesitation at all and the '99's and 00's that I test drove also had no hesitation. I would definitely take it in for that.
I just bought a '95 Chev K1500, Silverado Extended Cab 4x4 with the 4.3L V6 Vortec, and a 5 spd. My mileage for the first two tanks has been around 15mpg. This seems low to me, but I'd like any numbers anyone might have from a similar truck. I've just changed the plugs, and air filter and hope that will help, but I don't expect a huge change. Is this the best I can expect from that small an engine pushing that large a truck?
mbonn, Is that mileage for city or highway or a mixture (if so, what percentage highway), and what axle ratio? If it's mostly city, I'd say that sounds about right. But if it's mostly highway, unless your axle ratio is 4.10, I'd say your highway mileage should be near 20 (or even above) as long as you're not too heavy on the pedal. If the plugs and filter don't help, here's a list of things I would check (some or all of these may be obvious, but a reminder can't hurt):
PCV valve (just replace it for around $3 and 2 minutes work) EGR valve spark plug wires (are they original? if so, they probably need replaced. Replace them with low-resistance wires) tires inflated to at least 35 lbs.? (mine say 44 lbs. max so I keep them at 38 lbs. cold) wheel alignment catalytic converter clogged? (that happened to me on a jeep cherokee with the 2.8L V6. I couldn't get better than 16 mpg and it seemed really under-powered so I sold it. The guy that bought it changed the cat. conv. and said it had tons more power and was getting over 20 mpg) fluid level in rear differential dirty engine oil?
The mileage was a mix of highway and city. I'm ashamed to admit that I'm not sure what the axle ratio is. How do I find out?
I inflated the tires correctly, but I'll definitely change the PCV valve, and the wires. I think I'll hold off on the catalytic converter until I'm really convinced that there is a problem. (Them things ain't cheap!)
I noticed a power/response difference when I changed the plugs and the filter, so I'm hoping that this tank of gas will show an improvement in mileage as well.
Anyways, thanks for your tips, and I'll keep you posted.
i think your average MPG with the 6.0 would be in the 12-13 range once broken in. some folks around here are reporting highway mileages of around 15. plus the 6.0 is a bit more powerful than the 5.7.
i don't think the fuel costs will be as bad as you think.
My 2000 LT, 5300, auto, ext. cab, ~3000 miles, gets a little better than 16 mpg. I have written an excel spreadsheet to keep up with cumulative mpg as well as by the tank. Post info. if anyone would like a copy of my spreadsheet that will do all the calculations for you.
Could someone give me any information on what kind of gas mileage to expect on 1999-2000 F250 CC,SD, 5.4L with 3.73rear end? I ordered this truck on 9/15/99 but still haven't heard a word about delivery.
Very impressed with the gas mileage on this truck. I do have Snugtop shell on it - extended cab, 6.5 foot bed. It is very hard for me to average less than 16 mph. I am not easy on the throttle - generally set cruise at 83 mph (this is New Mexico) - and don't hesitate to run 90+ mph to get around the semi's on I-40. I have seen nearly 18 mpg over long distances - better in perfect (tail-wind) conditions over short distances. Driving at 6,000 - 7,500 foot elevation most of the time. Could not be happier - had a 4X4 Ranger (4.0) that hardly did better - underpowered for me. It was no match in terms of a real truck plus the comfort factor and then almost the same gas mileage!
Comments
My last four fill-ups are below:
448.7 mi. 22.255 gal. 20.16 mpg
442.6 mi. 21.940 gal. 20.17 mpg
487.5 mi. 23.402 gal. 20.83 mpg
450.2 mi. 21.188 gal. 21.24 mpg
My truck actually has better range between fill-ups than my wife's Buick LeSabre. Of course it also has a 25 gallon tank to her 17 gallon tank, but still... I'm impressed with GM trucks!
I can only guess as the '99's and 00's start breaking in, people will be reporting 22's and 23's since their engines are more efficient.
-powerisfun
these 13-15 MPG quotes from using 93 octane? How
about an ethanol mix?
The mpg figures you quoted are close to what I get with the V-10 and 4.30, and I get the benefit of the extra power. If you get the 3.73 axle ratio with the V-10, your mpg should improve quite a bit. I don't think you will be disappointed, especially with the increased V-10 power for the 2000 model.
Anyway to cut a long story short they reckon that a tonneau cover reduced drag by between 20 & 30%. This all came down to the fact that the air is prevented from entering the truck bed and becoming even more turbulent. Not sure if I believe the figures, but this must translate into a significant increase in economy.
I would greatly appreciate it if you would post
where you read that article. It sounds very interesting. Thanks.
-Tim (powerisfun)
Geez, you don't half like making me work don't you. I was fairly convinved that I read it on the web, but I couldn't remember where. Anyway, after an exhaustive search I found it.
http://mars.acnet.wnec.edu/~ehaffner/did.htm
I was slightly wrong on the reduction, it comes out at a 12% reduction, but still significant. The 30% saving was the new design they propose.
They also do some comparisons with tailgate down, removed etc. Fairly interesting (for a university study).
have a hard tonneau cover on my truck and I'm really happy with the mileage I'm getting (I have a '98 GMC Sierra x-cab Z71, 5.7L, 3.73 rear, 9900 miles, and I'm averaging over 20.5 on my last 4 tankfuls).
If you read the website listed in the above
response by andy_jordan, it shows research into
wind drag on pickups. According to them, leaving the tailgate down reduces drag by something like
3%. Oddly enough, removing the tailgate or installing one of those nets in place of the tailgate disrupts the flow and causes an actual
increase in the drag. A tonneau cover decreases drag by 11.8%.
-Tim (powerisfun)
With the taigate down, the separation point occurs at the top of the cab. This means the pressure drag occurs over the the back window, and the front of the bed, which is a larger area than just the tailgate.
Pressure drag is called such because the pressure on the back of the vehicle is lower than that on the front of the vehicle (because of the more turbulent flow, from separation).
Now, that study was done on Ford production trucks, no aftermarket. Lift kits, tires, toolboxes, etc, can certainly change things.
I am sure exact results will vary depending on any number of factors, but the airflow pictures are quite interesting.
tailgate, now I won't bother and will look into a bed cover. I drive a '99 Dodge QC 4x4,AT, 5.9L with the 3.55 axle ratio and 11300 miles. I have kept track of the mileage on every fillup, the worst was 13mpg towing a 2000 lb tent trailer (I think the gas was oxygenated because I got the same lousy mpg when I filled up at that same station again and I was able to get 15.8mpg on the same trip from other fillups). The best mpg has been 16.8 twice, living in AZ these figures are always with the AC on. These figures are with the tailgate up and a K&N filter, I will be putting the paper filter back in for a run or two on my 300 mile test route in the next couple of months as I want to see if it makes any difference now with the engine a little more broken in (the K&N filter went in at 7000 miles and I don't have mpg on that route for the paper filter). I will post the results.
My 92 F-250HD 4x4 with the 351 and 3.55 only got 14-15 on the hwy. That's about what the new Ford V-10 with the 3.73 gets and the new V-10 has a lot more power. Same mpg with significantly more power. I'd consider that an improvement. Maybe someday they will make a gas engine that will get close to 20mpg and can effectively move a 7,000 pound truck, but for now, they call it a diesel.
Yawl must be driving too slow.....
Thanks
Good luck whatever you decide.
-powerisfun
-powerisfun
The hesitation also doesn't sound right. My '98 has no hesitation at all and the '99's and 00's that I test drove also had no hesitation. I would definitely take it in for that.
-powerisfun
Is that mileage for city or highway or a mixture (if so, what percentage highway), and what axle ratio? If it's mostly city, I'd say that sounds about right. But if it's mostly highway, unless your axle ratio is 4.10, I'd say your highway mileage should be near 20 (or even above) as long as you're not too heavy on the pedal. If the plugs and filter don't help, here's a list of things I would check (some or all of these may be obvious, but a reminder can't hurt):
PCV valve (just replace it for around $3 and 2
minutes work)
EGR valve
spark plug wires (are they original? if so, they
probably need replaced. Replace them with
low-resistance wires)
tires inflated to at least 35 lbs.? (mine say 44
lbs. max so I keep them at 38 lbs. cold)
wheel alignment
catalytic converter clogged? (that happened to me
on a jeep cherokee with the 2.8L V6. I
couldn't get better than 16 mpg and it seemed
really under-powered so I sold it. The guy
that bought it changed the cat. conv. and said
it had tons more power and was getting
over 20 mpg)
fluid level in rear differential
dirty engine oil?
-powerisfun
I inflated the tires correctly, but I'll definitely change the PCV valve, and the wires. I think I'll hold off on the catalytic converter until I'm really convinced that there is a problem. (Them things ain't cheap!)
I noticed a power/response difference when I changed the plugs and the filter, so I'm hoping that this tank of gas will show an improvement in mileage as well.
Anyways, thanks for your tips, and I'll keep you posted.
i don't think the fuel costs will be as bad as you think.