I appologize if this has already been answered elsewhere, but i recently bought a 99 TJ 2.5 4 cyl. and it has some difficulties when its cold/damp outside. I already replaced all the plugs, plug wires, distributor cap and rotor, thinking that was the issue, but not much improvement. It starts and runs great on warm dry days. On damp days when it does start, it sputters pretty badly, specifically around 2,000 rpm, until the engine warms up then it runs just fine.
Not sure what else to do. Ruled out the IAC, and obviously my home tuneup did no good, any suggestions??