Earlier today I was noticing that I seemed to be getting better mpg at 17-1800 rpm vs a slower speed and 1600 rpm. Since I have the 6 sp auto should I just use 5th gear instead of 6th and will I get better mpg??

 

I cant speak for your common rail.. but I can speak for every single other gas car, and my 2 diesel trucks and my diesel car.. with standard transmissions, running the rpms up (in a diesel) to about 2k or so, or longer on hills, is the best for mileage. Diesels do NOT like being short shifted.
What I've noticed with all of my autos though, is the lighter on the throttle, the better the mileage. Now keep in mind, every single car, truck and motor are different. But "typically", standards like more rpms, and autos like being shifted early.

I know that people with tdi Volkswagens get 70+miles per gallon leaving their cars in 4th gear on highway runs (Can you say 3500-4k rpms in a diesel?). Not good at ALL for the rotating assembly.. but great for mileage.

 

i get better in 6th gear around 1500 rpms

 

Keep above the 1600 .. closer to the 2000 if you are towing.

 

I get the best around 75 mph, 1600-1700 or so. Best Ive done with my truck is 25.6 and thats with traffic jams on the way from MD to CT

 

what kind of mpg increase can i exspect with deletes , what power level is best on HS for mpg's, only getting 13.2 now on a good day

 

you fixin to be a very happy guy Beerlvr.

 

When empty Im getting around 18-19 unless bad headwinds then its 14. Towing 34ft trailer 9-12.