355 5.2 Motronic starting idle problem...

Long story, but here goes:

For the past year and a half to two years, I have had an intermittent low idle upon cold starting. Car would idle around 750 rpm. Shutting down and restarting, the car would idle properly at around 1400 rpm, until warm where it would settle in at 1000 rpm. Once in a while it might take two or three tries to idle properly or only idle at 1,000 rpm. As time progressed, the problem would manifest itself more frequently, and occaisionally even when hot. Took it to the dealer, and they said it was a dirty Bosch idle regulator valve/motor...so they cleaned it. Problem persisted, so I decide to go ahead and replace it, if that was what they thought was the problem. It didn't help. I spoke to 91TR (Steve Magnusson, the diagnostics master) and he suggested the Bosch throttle position potentiometer may be suspect and to test it. I did, and seemed to get a couple intermittent readings after dozens and dozens of tests, so I replaced it. Car started perfectly for two months, then the problem has returned, but seems to only occur when cold, not hot. (although I sense it might be happening when hot, but very mildly). In any event, I decided to replace the Bosch water temp sensor, that tells the motronic the engine is cold and needs cold idle. No help.

I admit more detailed diagnostics would help here, but the access to some of these parts is difficult, particularly if I want to test them while the problem is actually happening.

Before I buy another throttle position potentiometer, I though I might ask if anyone else is having this problem. I had the dealer look into it again, while I was having my clutch renewed, and of course, they could not get it to act up. It is doing it every third or fourth cold start for me.....