[ErieGT]

Remove some air, If you leave it at 40psi you will be replacing tires very quickly. To much air will wear the center of the tire and not enough air will wear the outsides of the tire, you need the proper amount of air to maintain your tires and stability. Read the side of the tire as stated by 06GT4me. If you're only getting 12mpg, I only have one suggestion: Let up on the gas.:winks