Well I called DP-Tuner to discuss my concerns with my mileage after a recent trip. I drove from Virginia Beach VA to Lynchburg VA and back a few days ago. On the way up I drove 267 miles total and 134 miles before the needle moved off the F on the stock tune before I topped off. I stopped to fill up and I could only get a little over 10 gallons back to the top! Thats about 24 to 26 MPG
Well I really tried to do the dance at the pump to get as much fuel back in the tank as before I left. Maybe the pump I was using to top off with was more sensitive than the one I used in VA Beach since those results are as Jody said unheard of.
On the way back, I switched to the 80 econo tune. After about 54 miles, the needle moved off of the F
I drove until I hit about 94 miles and decided to go back to stock to save on fuel. Between the 80 econo and stock only yielded about 16MPG.
After talking with Jody, He thinks it is the result of the grey CPS and suggested to go to a black one. I got a black one at NAPA today and installed it and I am running the 80 econo tune again. He also mentioned he fact that the gauge in our trucks is about as acurate as a weather forcast and I think I am seing that more and more. I have only had my truck for about 4 months and have only topped it off 4 or 5 times so I am still learning. On this tank so far I have gone over 80 miles with 60/40 city/highway driving and the needle is still on full
Before I filled up the last time, the needle moved off at 103 with the stock tune and same city/highway mix. I put in 7.5 gallons so that comes out to 13.7MPG. So with that said, I guess there is a pretty good fudge factor when it comes to filling the tank. I was thinking to use a dipstick to measure the level in the tank without sitting there for 40 minutes trying to top off the tank. Does that sound plausable or just stupid? Obviously the problem is not with the chip, but with the fillup process and possibly the CPS as Jody suggested. I am watching my mielage once again to see if the black CPS helps. It was so nice to go back to the 80 econo, my truck was such a turd on the stock tune.