Newbie with surging 5s-FE

[stormhawk]

I recently bought a really nice '90 Celica with a transplanted motor from a '96 Camry. Overall the car runs excellent but I have a small problem I can't seem to get past. Occasionally with the AC turned off and the motor warm the idle with jump from 1100rpms to 1300rpms, drop back down and then jump back up. This cycle repeats while the car is idling in traffic. The idle is smooth and the car has plenty of power. I pulled & cleaned the throttle & IAC. That smoothed out the idle a bit but didn't really effect the surging. I don't exactly have a lot of faith in the guys who did the motor swap and I wouldn't be surprised if there was a conflict of some kind between the '90 and '96 wiring and vacuum routing. The car does idle high, but I'll hopefully fix that while in the process of diagnosing the surging. Car's a manual trans BTW.

[TrailDust]

Here is a past thread that discussed surging at idle, but there are many others as this is a common issue. I'd recommend using the search feature to locate other threads that discuss idle surging.

[stormhawk]

That thread is perfect, lots of things I hadn't even thought of.
Thanks.