Idle Problem
 

Ive got a 1985 944 NA with a idle problem, it will sit there and idle up to about 1300 and drop to 900 and it will do this repeatedly when it is warm. idk what it could be, i was thinking maybe a vacuum leak or a plugged vacuum line, but not positive on what it could be, anyone got any idea?

yea sounds like a vacuum leak.

ya thats what i was thinking, i was thinking about replacing all the vacuum lines all together, that way i don't run into this problem again.

could also be a dirty ISV (idle stabilizer valve) but the hunting idle usually only happens when the motor is cold..
You can clean it by unplugging a vacuum line & putting it into a glass full of sea foam, then start the car & let the sea foam be sucked into the intake, then turn the car off & let it sit for 15 min, then restart & let it run thru for about another 15 min.
BTW it will smoke ALOT - don't do this in the garage

seafoam is good idea. forget garage, you do NOT want to do this in your neighborhood, unless you want to be hated by all of your neighbors. i've heard of people getting ticketed for seafoaming on public roads. it doesn't create "a bit of smoke" it creates a fog storm for half a mile. SmileWavy


http://www.youtube.com/watch?v=P-4EfjUU5o4&feature=related

this whole idle thing came about after i had the car F&I injected. there are three cans of cleaner, one can goes in your gas tank, and two go through the intake. after i had this done is when the idle problem came about. after the injection the car ran 100 times better then before with exception to the bad idle. and it only idles like this when it gets warmed up. and if i go into a store for a couple minutes and come back out and start it up to leave, it will idle at about 1400 and if i touch the gas it will rev even higher and stay there without dropping back down, then if you give it a second it will start the bad idle again. i will try to get a video of it so you better understand what im talking about.