[mejulihn]

This topic comes up from time to time. The usual suspect is a bad throttle position switch. But having replaced mine with no improvement, I have been frustrated in diagnosing the cause of a mid-RPM stumble. Finally took the car to my pro 914 wrench for some other work and asked him to also check the timing. When he checked, the factory timing marks were no longer visible on the fan. He removed the fan and used the template I downloaded from Pelican Parts (thanks, PP!) to add new marks and reset the timing. Turns out the spark had been very retarded (no remarks about the owner please). Just reaffims what DD and others always suggest, check the basics first!