Rep Power: 195

So after I cleaned my throttle body and surrounding sensors I get a warm idel surge. The car starts and runs fine. Cold idle is fine.
After being driven when I put it in N or P the surge starts. It is a higher idle that drops briefly then back to a faster idle then drops again.
Since I have been dealing with the oil leak I haven't messed with it. Pulled the head off, took the intake manifold off. Cleaned everything inside and out. New gaskets for the head, intake, exhaust and surrounding areas.
Re-cleaned the sensors on the throttle body and reinstalled everything.
Surge is still there. It will go away when I disconnect the throttle angle sensor and plug it back in.

Took it for a 20 minute drive to make sure everything was working for the head removal and when I pulled back into the garage the surging wasn't happening. Thought maybe the drive had cleared it.

Here's the weird part.
When I turned off the head lights the surging started again. It would stop when I turned the lights back on (either parking or head lights)
Not sure if the lights draw enough power to cause the idle to increase above the range for the surge to happen.

94 DX with a D15B7

Anyway, any thoughts on what to check would be much appreciated.

Thanks,
Brian

 
Rep Power: 195

After further trouble shooting, when I cover the lower hole in the TB the surge stops. This leads me to believe it may be the FITV -( Fast Idle Thermo Valve) causing the issue. From my understanding there should be no vacuum in this hole when the engine is warm, but when I covered it, it nearly sucked the finger tip of my glove off.

Am I looking in the right direction?

 
Rep Power: 195

Finally fixed the problem. Ordered a new FITV and replaced that first. Made no difference.
Found a used IACV on Ebay for $20 and took a chance on that. Installed this evening and it seems to be working OK. Hope that fixes it as I don't want to have to order a new TB.

 
Rep Power: 285

Did you do the idle learn procedure after doing all this stuff?

 
Rep Power: 195

No I didn't. Thanks for the reminder.