random engine revving problem
 

Howdy Porsche friends
I have a 86 Carrera. Drove the car about 20 minutes. Parked and went into a store.
Came back out, started the engine and the engine started revving on its own. Up to 2800 rpm and back about 5-6 times, then back to idle. Put it in gear to drive away and it died. Had it towed home. Next day went out to start it and all was back to normal. Next day had one random rev to 2800 then normal. any ideas?
Someone suggested maybe coil? DME?

Thanks in advance :)

The first thing I would check for are vacuum leaks . . .