hello everyone:
I have been having an issue with my 94 cab. I has been hard to cold start and has been "hunting" an rpm while idling. I have already done a bunch of other work to the car and there wasn't a lot of things left that it could be. But when I went looking for a new ISA I discovered that Porsche no longer makes them. I did find a couple of threads here and on other forums when they were being disassembled and the O ring replaced. I didn't really want to go this route and I worried that I would end up with it totally screwed up if I tried. So after much searching I found a thread where it was stated that the ISA from a 97 Hyundai Elantra would work. So I figured for 40 bucks shipped I really didn't have much to lose. Lo and behold that darn thing works perfectly! Anyway I thought I would share this with everyone in case it was not well known.

both of them, side by side.

 

Sorry to be so naive but what does ISA stand for?

 

OMG I love this—97 Hyundai Elantra. I recently did a deep clean as part of my top-end rebuild and thought I would replace this part—until I saw Porsche prices. It's a simple thing - so I took it out and thoroughly cleaned. Seemed to work on a bench test but who knows under real world conditions? My car doesn't like to start on the first turn of the key - but reliably fires up on the second turn. Had annoying rough idle issues moving out of the driveway but no issues after the first two minutes. Don't know if the ISA (Idle Speed Adjuster) would be the issue or not.

Appreciation for the part referral!

 

replacing this part has definitely made a difference. I have the same issues that you are having. when it's cold outside and the engine is cold, the car will start on the 1st crank but it feels like it's running on 2 cylinders. however, if I shut it off let it sit for 10 seconds and crank it again. it starts right up. after replacing this part it is much improved but still not perfect. I'm chasing that last 5%. I'll be working on it today, trying to find that problem. my guess is a vacuum leak. I have noticed that since replacing this it is running much smoother when it's warm.