Well, just got this car 2 weeks ago. Out of nowhere (as in I didnt do any work to it before it happened), it starts accelerating with tons of hesitation. Now if I hold the accelerator steady in neutral, the tach starts falling and finally rests somewhere lower. Sometimes it'll surge up and down. As it gets warmer, it starts changing the idle up a whole bunch. Once at normal operating temp, it runs pretty good. I already ruled the TPS out, it reads okay in all usable positions. Rotor and cap are good, dont know about anything else. Two theories: some kind of coolant temp sensor, or a plugged cat. The exhaust sounds muffled, but I cant tell if that noise is being caused by poor firing conditions. Any thoughts or common problems with these damn things?

 

Run the codes.

http://minimopar.knizefamily.net/fault/index.html