trying to find idle !!!!

[P944GUY]

87 944, when my car is cold ( first start ), and when it is idling it seems to surge a few hundred rpm's and then drops down and comes back up ( around 1,000 rpms ) seems to do this surging/coming back down thing until it's hot. What can I check ?? I had a major vac leak in the large rubber boot and I replaced that. Could it be the idle regulator, throttle switch or different vac leak ? How do you check those? Also, I took the throttle assembly off and cleaned the heck out of it. Also, it seems slow for the rpm's to come down when revving it up (throttle switch?) Any ideas will help, thanks

[Scott R]

I had this problem last weekend and tracked it down to a bad CO level coming from the AFM. I had to drill the adjustment plug out and redo the air/fuel mix. Now it works just fine again.

[P944GUY]

Hey thanks for the reply> I took my car in to my mechanic this afternoon and he adjusted the CO and some other things. There still is a slight surging of the idle, but thinks that the idle control valve is carboned up, could be after 125,000 miles. I'm gonna wait til I need to pull of intake manifold to replace it.

[3sonfather]

Did you check the throttle switch function? You can usually hear the click if you move the throttle plate by hand. There are three settings: throttle closed, throttle not closed, throttle wide open. If this isn't set properly, your DME might think that the car is not at idle. Easy to check.

I have the same problem in my 87 944S, except that it continues when the car is hot, the idle speed bounces from 500-1500 rpm, I replaced the throttle switch but that didnt help, also I looked at the vaccum hoses but I couldnt find a leak, if anyone can help me please let me know, I dont want to spend $150 for a new idle speed regulator if that wont fix my problem. Thanks!
Maciek, 87 944S, 86 944 n/a

[Scott R]

If you come down to the idle air regulator. email me I have an extra you can have.