The previous owner of the truck was mainly highway driving ... now i drive mainly city (about 90%). My question is if I reset the PCM would my MPG get better,worse or stay the same? Am I better to keep the PCM programmed with the previous owners highway driving or reset it to my style of driving. I don't wantto reset it and get worse MPG. What do you think?

 

the more u drive in city the computer will learn that and adj the fuel adaptives to such. If u reset it it will take time to relearn but still turn out the same.