Oops, sorry for an empty post - twitchy hands from too much brick aggravation :)

I'm having what could be a similar problem. My 1991 944T began showing hot start problems, which escalated into stalling underway, and cold start roughness as well. When it wants to die, I can keep it up by holding high idle (say 2000 RPM), and within a minute or two it usually smoothes out - until the next episode. The RPM is twitching, the fuel pressure regulator is new, I can hear the pre-pump, the FI relay looks great inside, the ignition amplifier feels cold to the touch.

Any suggestions? Particularly, before I go replacing parts left and right, is there an independent way to test the ignition amplifier and radio suppression relay?

Also, can one think of a scenario when an intermittent vacuum leak would cause these symptoms? Something along these lines: a vacuum leak opens the FPR at idle and floods the engine. When I open up the throttle, the "leak" past the throttle plate becomes large compared to the problem leak, and the car runs OK at 2000 RPM.

Thanks in advance,

Alex