Hi folks, I have a '94 22re with a surging idle problem. It happens ONLY in Park or Neutral.
I've seen many threads about a similar problem either with the brakes engaged or with the A/C on, this is neither.
Any suggestions on where to begin troubleshooting?
Thanks a lot!

 

What rpm is the engine idling at when warm and in gear?
It could be as easy as just turning down the idle screw on the throttle body. There is also a small Oring on the screw that can shrink with age and loose its seal and let air by.

 

I don't have a tach but it doesn't idle high. Probably around 700rpm...
I did try adjusting the idle screw to no avail.
Should mention, the surging comes only when the engine is up to temp.

 

Air bubble at the engine coolant sensor to ECU, or idle valve. One of those could be faulty but more unlikely than an air pocket.

You need a tach, three easy ways are a timing light, good multimeter, or cheap pod. I've never met anyone that can count the 50rpm range you need to set these within.

 

Yes, basic, simple things first; What's your idle? I had surging idle problem when I stop from freeway speed with AC on - fixed by fixing idle RPM.
Very happy with my Actron CP7529 Digital Timing Light Link: http://a.co/7gY5llh
Good investment for a truck I wanna keep for as long as I can safely drive. (Heck, if and when I turn 90, I'll have someone else do the driving for me- LOL! )

 

Just wanted to follow up here. Thanks for all the suggestions.
Turns out Robert M was right, idle screw o-ring was the culprit.
Somehow backing the idle screw way off then resetting it fixed the problem.
Truck idles perfectly and the repair was free! Thanks so much!

 

Glad it was a simple fix. I put silicone sealant over the thing once idle is adjusted.

 

If the surging ever returns, you could always replace the "O" ring as they get hard and brittle over time: https://22reperformance.com/intake-e...r-screw-o-ring

It is nice when you find a simple and easy fix!