Poor Fuel Mileage

[hoogkar]

Got truck back from dealer for the fifth time - lost 7 mpg from normal - they replaced fuel pump to in tank conversion - replaced front pinion bearings - replaced rail pressure sensor/regulator - reflashed ecm-- NO CHANGE!!!



This time they replaced all six injectors mileage has gone from 12. 5 mpg unloaded, highway at 70 mph to 21. 5 MPG. It took a while but they finally got it right. THIS WAS ALL UNDER WARRANTY, SPEAKS PRETTY GOOD FOR THIS DEALER!!!!!!!! I did have to asert a little pressure, but in the end it worked out great.



I hope anyone who sees a drastic drop in fuel mileage like I did cann use this informationt

 

[RCMerrill]

What if you allways had bad millage 8-12 mpg unloaded the only thing i have done to the truck it put 315 Bfgoodrich tires on it when it was new. the dealer had me put the original tires on it & said it is wind drag & i would gain 10 mpg back. after spending all that money guess what i still get the same millage. my truck is an 06 2500 auto 3. 73 gears 4x4 larime any suggestions!

 

[DerekW]

how many miles on it you may need to break it in so you can get mileage back. regardless working on airflow from cummins except everything other than aftemarket single turbos can help mileage considerably. im getting 24 last i checked. Im waiting to get some free time to do the latest testing sicne new injectors and other changes. i do know I filled it up and drove 156 miles before the fuel guage dropped to the point where it was even with the full line on the fuel gauge. I do have gdp vent. then mileage dropped like crazy when I had 10 minutes to drive around 40 miles. would you like me to do a mileage test tommorow and report back??? PM me to get my attention if u want me to report latest numbers and parts installed.

 

[DerekW]

Got truck back from dealer for the fifth time - lost 7 mpg from normal - they replaced fuel pump to in tank conversion - replaced front pinion bearings - replaced rail pressure sensor/regulator - reflashed ecm-- NO CHANGE!!!



This time they replaced all six injectors mileage has gone from 12. 5 mpg unloaded, highway at 70 mph to 21. 5 MPG. It took a while but they finally got it right. THIS WAS ALL UNDER WARRANTY, SPEAKS PRETTY GOOD FOR THIS DEALER!!!!!!!! I did have to asert a little pressure, but in the end it worked out great.



I hope anyone who sees a drastic drop in fuel mileage like I did cann use this informationt

sounds like a dealer i might want to goto if i hadnt gotten tired of DC and dealers.

 

[JDerrick]

21. 5 MPG !!!!!!!!!!!!!!!!!!!!!!! My 06 has never even drempt of this type of milage. the best i have ever had in it was 17. 4 on the computer. Mechanic friend in vegas re-flashed it when I was in town for MM 07, that helped a little bit , now runs around 14. 5 ish. I keep my foot out of it, and run the edge box on setting 1 just to try to get some better milage out of it. New injectors eh?? hhhhhhhhhmmmmmmmm I am still on a dealer search as my local dealr is worthless, I am planning a trip to Twinfalls, Idaho to talk to the folks up there. I should print this thread and take it with me. Oo.