Idle Surging

[SurfnSun]

Hey guys last week I went to get my car out and while it was idling I notice a bit of surge, the revs bouncing up and down. I turned off the AC and it smoothed out a little. But then when driving the car everytime I pulled up to a stoplight and pushed in the clutch the car would die.

My first thoughts was a bad MAF....any other opinions? I have only started the car once since to wash it, so I don't know if its still doing it or not.

 

[69MyWay]

Any check engine light?

Do you have a good quality scanner to read and record data?

When I have had this happen in the past, it has been a dirty stuck idle air motor. This may be even more subject to getting gunked up with the extra pressure and blow bye created by the turbo pressures.

The idle air control motor is in the front of the intake on the throttle body housing. There is a specific procedure to getting it to reseat after you remove and clean it all out.

You can spray throttle body housing cleaner up in the bore, and use it to clean the needle and contact point.

Usually, it is reset/idle rest on your year model by turning the key to run with the diagnostic plug grounded. Waiting about 20 seconds, then shutting off the car. Now you unplug the idle air motor. Fire back up and set the idle to the desired level by adjusting the throttle plate screw. When happy. Shut down, reconnect the idle air motor, go drive the car over 40 mph for a few miles.

Come back and reset the service engine light soon, and you are there!

Now, all that applies to a non-turbo car. If the same, you should be able to diagnose and be up and running.

BTW, a stuck idle air motor will not always generate a check engine light.

 

[VetteGarage]

Had that problem on my 90 automatic. IAC was bad.
Constant high idle on my 89 was caused by by the ECM.

 

[SurfnSun]

thanks guys....

yea there were no codes, i had completely forgotten about the stuck/bad IAC. Had the same problem with my 85 one time, tapped the TB with a mallet and it went away.

I'll go drive the car tomorrow, if it doesn't act up thats probably what it is.

 

[SurfnSun]

hmmmm started the car and it ran fine. Turned on the AC and drove....the it died when I pulled up to a light. Shut off the AC it was fine again.

Sounds like the IAC to me....thoughts?

heres turbo snag #1 you can't even see the IAC with the rams horn in the way.