rough idle when warm
 

Hi all, I let my 968 sit for a while over the last 5 years. Finally getting a chance to use the car again. The problem I am having is when the engine comes up to operating temp, it starts to miss at idle and stumble real bad when applying throttle. If I come up slowly. say to 3000 rpm, the engine runs smooth and flawless. If I hold the pedal to around 2500 rpm or less, it will stumble and eventually stall. The warmer the engine gets, the worse the problem.

So far I have changed the injectors with new because one of them was stuck closed. It starts up cold no problem. Fresh gas, replaced the fuel filter, and just replaced the O2 sensor. From reading, it sounds like the engine is fine during open loop operation. What should I be looking at next, I don't have a fuel pressure gauge right know because I don't really feel like it is a pump or regulator problem as the issue is consistent at warm up.
Thanks, Don

I think I may have asked for help too soon. I found lots of water/moisture down in the spark plug access areas. Dried wires and holes and so far so good. Odd that it would only act up when the engine approached warm.