I've notice a couple of times on fill ups I get better mileage with the rear tank than I do with the front tank, I don't mean a little either I'm talking 12 or 13(front) 15 or 16(rear) I just noticed this.. if you guys got any ideas I'm all ears.... or eyes whatever

thanks

 

what year is your truck? My truck sometimes pumps fuel from my rear tank into the front tank, so it seems that the rear tank will be getting crappy mileage, but the fuel is actually just going into the other tank, not the motor. Mine is an 89, and ive come to the conclusion that my rear fuel pump is getting weak, so its not putting enough pressure to the dual function resevoir thing to switch it over completely.

 

Are you taking into account the fact that one tank is a few gallons larger than the other?

-Jon

 

sounds like the "Cross fuel flow" recall problem . if it is back feeding into another tank there is a recall out on that .