I have a single cab 2003 Duramax. Nothing to extreme done to it. I'm running a PPE Excel programmer. I have been keeping track with my fuel mileage here lately and what my calculations are... Doesn't seem right to me. Last time I calculated it, I am getting only 14.7mpg. That to me seems like its not getting enough mpg?? Also whenever I go to put the petal to the floor... It flutters out and pauses in between 3rd to 4th gear... What might be the problem?? Any suggestions would help! Thanks!!

 

Tell us more about your rig. Does it have larger tires? Thransmission built? Any other mods?

The first think i would do is monitor the desired and actual fuel pressure. Is it throwing smoke when you accelerate?

Jason

 

Thanks Jason for replying first off!! Ok, my truck is pretty much stock. Like I said it is a 2003 single cab and the only thing that I have done to it is I have a PPE excel programmer, with a PPE boost valve. I bought a brand new set of 315-75r-16 mud Terrain tires for it with a set of 16x10 eagle alloy bullet hole wheels. Just hit 200,000 miles on truck. I honestly had never checked the fuel mileage before I put the tires and wheels on it, but when I did check it this first time it just seemed to me like it was lower than it should be getting. The truck has no built trans either. Everything mechanically is bone stock, and it does not throw any smoke either. Only time that I've seen it smoke barley is on the past couple of cold mornings when I first crank it, and it smokes just a little bit of blue and white mixed smoke. Other than that it's fine. I am looking to push it on up to the 600hp range in the future and any recommendations on What I need to do to get there and it be solid and hold up would be greatly appreciated as well! Thanks, John.

 

what tune have you been using on the programmer? with that size tire, you may see mileage drop as well. but the hesitation between third and fourth is due to the programmer. if you have it on the hot tune, you stand a good chance of blowing your trans out. its hesitating because the allison is trying to change gears without slipping.

 

bigger tires will mpgs.