ISX 2350 485

[zare6]

Hi gentlemen, I want to bring this back on track. The boost may be high and has always been 38 psi right from new and the fuel mileage was 7mpg nothing has changed but the mileage on the truck. The egr the dpf all the emissions have been checked and or cleaned. So here we are 200000 miles 38psi boost pulls like a freight train but 5 mpg. I decided to do a custom tune, the boost went to 43psi pulls incredible fuel mileage is now 4.5 mpg.