Porsche Repair: idle problem on my 944, engine tester, pointer

Question
hi,this is my problem with my 944 from 85/2:
i dont know why from time to time when i drive and after i take out from gear my idle pointer want to go very low (under 800rpm)and then go back on 1000rpm and down, and up..and so on.i was with my car to a engine tester and they told me that my idle was to low,they fixed but after 1 month the idle was playn again..what could be the problem?

Answer
Hi Daly,

I'm pretty sure you can do this...if not please write back.  Coincidentally, another 944 owner asked a very similar question on 1-17-2006 and he's had a couple follow-up questions as well.  If you could check my responses to his questions I think it would shed some light on your idle problem.

Dave