help...06' poor MPG

[TFucili]

I am looking for a crew p/u to haul my 32' 10k 5er, and to be honest there are some good deals on 8. 1L 6speed alli's and with the new specs, and the motor being $5500. 00 less and owners getting 8-10 mpg towing and 14-16 mpg empty it seems very competitive with the diesel. Or I will look for an 03-04 QC 5600?

I had an '04 8. 1/Ally. Besides being a LEMON, it got 8 MPG pulling my 7x14 enclosed MC trailer, and never reached over 10 empty. The 8. 1 is a real hot rod around town empty but doesn't pull worth a darn below @2200RPM, just falls on it's face. I don't deny your mileage is unacceptable, but that big block Chevy is NOT the answer. Been there... done that.

 

[TylerMartin]

MPH issues fixed!

Well I finally got my truck to the dealer the other day to check out an array of problems that I've been having (Phantom warning lights, very poor MPG, truck dying/surging while accelerating, and poor tach gauge performance). They had the truck for a day and couldn't find a single thing wrong with it during the road test, but they Reflashed the ECM and updated it with the Hard start/white smoke TSB. They also changed my pinion factor for the 285/70/17 tires I'm running. I've put 500 miles on since then and I must say that it is a totally different truck!



It seems to be running a lot stronger with faster turbo spool and not even the slightest hint of surging or dying under WOT acceleration. It also seems quieter with less pilot injection noise (rattle). All my troubles are gone (for now anyway).



The other amazing thing is that my mileage has improved significantly. I've gone from 11-12 MPG to a solid 18. 5 MPG after this reflash. That is hand calculated traveling 65 MPH empty for the last 500 miles or so. I now have about 13000 miles on the truck.



I'm not sure if the TSB did anything to my mileage but I think my truck just needed a "re-boot" to wake it up. Anyway, now I could not be happier with the mileage and performance. It makes me love my truck even more! For those with poor mileage, it may be worth it to re-flash your ECM and/or get you pinion factor changed to see if it does anything. Worked for me!

 

[troll3193]

I would have to agree, something must be off. . I have an 04 4x4 with 4. 10 axles and get about 17mpg unloaded (~75MPH) and about 10-11 towing 9500lbs...



I also agree on getting the dealer/cummins to figure out the root cause before modifying it. .



Bryan