[CarPsyco84]

If your fuel trims are going that rich on the Medium and high trims, somthing else is wrong with the O2 senser or wire or somthing, cause I don't have a heater in my O2 either, and it only affects the Low trim, basicly idle, U have to be going like 30-40 steady for the Med. trim to get adjusted and like freeway for the high one to get adjusted...