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Chevy Silverado and GMC Sierra Duramax Fuel Mileage

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Comments

  • I don't know for sure but I suspect that the Juice chip causes the rail pressure to increase which allows more fuel to push through the injector per time. the mileage computer is likely programed to calculate amount of fuel used based on the time the injector has been opened. With the increased pressure more fuel is going through the injector than what the computer "realizes"
  • i have 05 lly and a 06 lbz,the lly is a one ton dully stock i got 15.8 mpg,but with dual 4"exhaust and ppe programmer i'm now getting average of 22 mpg on the highway,and on the lbz,it is a 2500hd crewcab shortbed stock i got 18 mpg but putting single 5"exhaust and ppe programmer i now get 22 on average,the stock exhaust leaves alot of back pressure there for taking more power to run the truck
  • Sounds like there might be an issue with your truck.
    I have the same identical truck as you and mine has been averaging 20 mpg from 55 mph to 60mph about 19mpg at
    65 mph and about 17.5 mpg to 18 mpg @ 70 mph.
    I also tow a 35 foot 5th wheel that weighs 11,000 lbs and I get 11 mpg to 12 while pulling flat surface at 65 mph.
    I checked the mileage the old fashioned way to verrify the computer but the computer was actually pretty close. The only thing I have done to the truck is replaced the stock donaldson air filter with a K& N AND I run Amsoil 15w40 heavy duty synthetic oil
    I hope this helps.

    Mike
  • I JUST BOUGHT AN '07 SILVERADO CLASSIC 2500 HD CC WITH THE DURAMAX THIS PAST MONDAY, THE DEALERSHIP FILLED THE TANK FOR ME BUT ON THE DIC DISPLAY IT SAYS I AM GETTING ABOUT 12.5 AND I HAVE USED A QUATER TANK SO FAR. A BUDDY OF MINE HAS A WORK TRUCK REG. CAB WITH 2WD AND HE IS GETTING CRAZY FUEL MILEAGE. THIS IS MY FIRST DIESEL SO I AM NEW TO EVERYTHING BUT I THOUGHT THE TRUCK SHOULD GET A LOT BETTER FUEL MILEAGE THAN THAT. ANY SUGGESTIONS ?
  • I suggest you reset your computer info (fuel used and MPG) Fill it up again as you do this and see what it does. I always get better than that and I got my 06 in July.. 20.2mpg at 65mph... 14-15mpg around town.. I have 8500 mi on it now..
  • I HAVE NOT TRIED RESETTING THE FUEL USED AND MPG BECAUSE I HAVE NOT HAD TO FILL UP AGAIN, BUT WITH THE 2500HD 4X4 CC WHAT IS THE IDEAL FUEL MILEAGE WITH 3.73 GEAR RATIO CITY AND HWY NOT PULLING ANYTHING. ALSO DOES ANYONE KNOW IF THE K&N AIR FILTER HELP AT ALL, WHEN I HAD A 1500 I HAD THE FIPK KIT AND IT HELPED SOME, JUST WONDERING WITH THE DURAMAX.
  • I have a 2006 Silverado 2500 Crewcab with the duramax and 373 gear ratio and 6 speed alison transmission.
    my actual gear ratio has changed a little due to the fact I took the 245 tires off and went to a taller 285.
    My truck has 25,000 miles on it and just installed a K&N air filter, I can't see alot of difference in mileage yet but it does not blow black as much under a load pulling my 11,000 lb 5th wheel. After taking into consideration the speedodometer is off 6 mph at 70mph and I actually travel 1 and 2/10th's for every mile showing on the odometer, I get around 15.5 to 16 in town and 19+ if I keep it below 70mph.
    I also get about 12 mpg pulling a 11,000lb high profile 5th wheel on flat grade.
    Point of consideration, When I installed the K&N air filter my check engine light came on within 10 miles of travel.
    K&N recommended I disconnect the negative battery cables from both batterys and leave disconnected for 3 and 1/2 hours. After I did this I reconnected the batterys and the check engine light was still on, but after I shut the truck off and restarted it for the second time the light cleared and has not come back on,
    Hope this info helps you.
    Mike
  • I purchased a 2007 Chevrolet 2500 HD 4x4 in October 2006. I have now got about 12,000 miles on the truck. I have been getting about 17-18 mpg normal driving (highway not towing). I purchased this truck (first Chev) due to the reported great fuel mileage of 20-24 mpg. What can I do to improve my fuel mileage. I am already driving slow at or below 65mph. Can anyone out here help ?
  • You are getting about what I get on my 06 chevy with 8500 miles on it... 18.8-20.2 mpg on the hwy with no load and 65mph.. I hope it gets better with more miles. I don't expect the engine to be broken IN until 25000 or so... Its too early now to tell.
  • I am only getting about 17-18 mpg at 65mph. I have not topped the 18 mpg barrier.

    Thoughts ?
  • If any one could help me, that would be great? Im thinking about buying a Duramax Diesel, but dont know if it is worth it. I travel alot ( approx. 200 miles a day ). What is the average MPG's on 2003, 2004, or should I look @ a different year? I was told the '03 and '04 in the 6.6 liter were the best, is this correct?
  • hoots10hoots10 Posts: 1
    I found your RE very interesting as I have your identical truck, just in a GMC. You sound like you know quite a bit about your truck, and as a first time diesel owner, I have some questions. I also went with 285's and raised the front end by turning up the torsion bars. The truck really looks like a truck now, but my problem is the front end is loose and rides rough. I think I need some longer/bigger shocks on the front end. Any comments? Also any recommendations on oils (synthetic vs. conventional), oil filters, length of oil changes would be appreciated. I currently us Mobile Delvac, AC Delco filter, and change every 5K. Can I run the oil longer? I'm also interested in putting an exhaust kit on. Does it void warranties and what benefits am I going to get? One last issue and I'm done. I was getting 18-19mpg at 65-70mph, but as I've gotten over 10K miles on the truck, my fuel economy has dropped 2-3 mpg...Is it time for me to put a new fuel filter on? I currently have 14K on the truck. I've been nothing but completely satisfied with the power, fuel economy, overall performance. And to think I almost bought a dodge. I'll never go back to a gasser or anything but GM. Forever DIESEL!
  • dddtdddt Posts: 13
    I have a 06 DD and bought the Superchips Flashpaq Tuner #2805. It does give you more "get up and go" but does nothing for the improved gas mileage especially while towing.
  • dddtdddt Posts: 13
    Anybody have any advice on how to get better mileage on the 06 DD 2500 while towing??? Or is 12-14 the best it gets. My brother in law has a Ram cummins and gets 16-17 towing the same weight as me. Any suggestions????????
  • dddtdddt Posts: 13
    Anybody have any advice on how to get better mileage on the 06 DD 2500 while towing??? Or is 12-14 the best it gets. My brother in law has a Ram cummins and gets 16-17 towing the same weight as me. Any suggestions??????
  • dddtdddt Posts: 13
    I have a 06 DD 2500 and get the average 17-19 city/highway combo driving. I once got the reported 21 mileage that you hear people talk about,BUT, I was driving the whole tank at 60 mph. "That is not how I drive." Towing I get approx. 12-14 towing a 7500 Travel Trailer, depends on the terain and head wind.

    I now have 18000 miles on my baby and pray that at least the towing mileage increases, if not, should of bought a Ram Cummins like my brother in law who is getting 16-17 towing the same weight as me. Go figure!!!!!!!!!
  • dddtdddt Posts: 13
    The big mirrors on the 3500 don't allow them to electronically be brought in. You must push them in manually. I had the electric ones on my 05 2500, they were wonderful, but they were samller.
  • exrenchexrench Posts: 3
    I just bought my first ever diesel truck 2007 3500 duramax 360hp, 650tq. I got 18.2 my first tank...by my third tank I got 14.7. I only have 1100miles on it now. I thought maybe a baffle in my muffler broke loose inside because of the hiss noise coming out the tail pipe at idle. I am not at all familier with diesels and dont know what to expect. I travel 25 miles to work at 40mph. I bought it to tow a 14,800lb 5th wheel. I was told the hissing is normal, and to wait a while before deciding about the mpg..
  • hunter80hunter80 Posts: 3
    Just wondering if anyone has either one of these and if so which is better and does it really help on MPG. Just trying to get the most I can on MPG.

    Thanks
  • coontie57coontie57 Posts: 128
    I had an edge on my ford diesel 7.3 and I could not see it helped the fuel mileage... lots more power thought.
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