I'm fighting a similar problem (rough idle, worse under AC load, especially when warm) with my 89 300TE. I've check the ICV, current looks good, but doesn't change under load. I also have a problem with the Cruise Control cutting out after a minute or two. Is it possible these two problems are related? My searches indicate that some cars had an integrated EA/ISC/CC unit. Does mine? how can I tell? I've checked fuel pressure, coolant temp sensor, throttle actuator. What next?