so the other day after checking out the charcoal canister on my 98 3.9l I decided to check out o2 response and fuel trims again to see if I missed anything. So I am reading the data at idle steady at around 600 or so rpm everything looks normal I slowly start to give engine gas and I mean slow so I can watch for o2s to drop out or something weird to happen and it does the engine all of a sudden races to about 1500 rpm. throttle is not stuck cause I wasn't anywhere near that rpm it actually did it all by itself. anyway I'm thinking the PCM is getting confused at the point of acceleration between the IAC disengaging and relying soley on the actual Tps and throttle plate. I think it senses it close and thinks that rpm have dropped out so it increases idle. IAC is new and it also did it once or twice with the old one. Tps is new, Map is new. Plugs, wires, cap and rotor all new o2s like I said are ok. Maybe time for a new PCM what do you think??