i did say approximately 115 mph.i knew the 3.4 was lower but not sure of exact numbers and didnt feel like looking it up.and yes it is a fuel supply issues.but impalassv8..slapping a set of tires on wont do it.has to have come from the dealer that way or tuned out of the computer.and...slow down man!!!lolhope you are driving in cold prone to ice conditions