Help! Unwanted "Variable" Idle Speed

[TBayToyotaBoy]

Well, the forums search didn't help too much, so here goes...I've taken apart and cleaned my throttle body twice in the past year, because the throttle sticks after long road trips (1400km from here to Toronto). I was careful not to mess with the Idle Speed Control, but now I'm getting wierd idle variations.

When I start the car cold (1990 V6), it idles perfectly--at around 800rpm (I set it 100rpm higher because my battery is old and the lights dim at stock 700rpm setting). If I turn the car off and let it sit for about 5 minutes, it then idles waaay high, around 1200-1400rpm. If I let the car sit for an hour or so before restarting, it idles at around 1000rpm.

Does my ISC need recalibration? Or could it be something more obscure? Any info would be most appreciated, to keep me out of the dealer bays where money flows like water!

Oh yeah, the car is standard, if it matters...

[JetspeedCamry]

Originally Posted by TBayToyotaBoy

When I start the car cold (1990 V6), it idles perfectly--at around 800rpm (I set it 100rpm higher because my battery is old and the lights dim at stock 700rpm setting)

How did you "set it 100rpm higher"?? 2VZ-FE has no adjustment...apart from holding the throttle plate open....(which isnt really adjustment )

[TBayToyotaBoy]

Actually, it does...the idle speed stop screw on the throttle body physically stops the throttle mechanism from returning any lower than you want it to...just unscrew the little nut, unthread the stop screw the desired amount, and re-tighten the nut.

It's not a permanent fix, because over time (weeks or months) the ECU adjusts back to "stock"...my cat has a small hole, so the idle adjusts to lower-than-stock (approx. 550-600rpm instead of 700rpm) and that's why I had to raise it slightly.