4AFE Throttle Body Adjustment

[RSTrider]

Can anyone tell me the correct way to adjust the throttle plate stop screw? I have a suspicion that someone altered the adjustment of this screw. I can't find any documentation on how to readjust it. What brought this on is that I recently took off the throttle body and cleaned it well. The idle adjustment screw had a lot of gunk on it that I cleaned off. Now, I can't adjust the idle lower than about 1100 RPM. I check for other air leaks but can't find any. The idle speed valve does not leak (with engine hot, I put duct tape over the ISV valve port inside the throttle body, but idle RPM remained the same). I'm pretty sure the throttle plates are letting too much air thru when shut, but i don't know how to check this adjustment.

Thanks.
Kevin

[Flashmn]

Did you put a new gasket when you put the throttle body back, also did you put the hoses into the right barbs?

If you didnt turn the idle adjustment screw, nor did you touch the throttle plate stop, then theres no way that the idle should be changed, right? so therefor the only possible way is that you have an air leak somewhere.

[RSTrider]

Yes, I installed a new gasket. Yes, all hoses are on correctly. Before cleaning the throttle body, the idle adjustment screw was turned in almost completely to achieve the correct idle speed, so it doesn't suprise me that now, with all the junk cleaned off the screw, I can no longer adjust the speed low enough.
This car has 330,000 miles on it, and I am not the original owner of the car. So it's very possible that someone messed with the throttle stop screw before I got it.

Kevin

[90 GP]

When engine is cold the idle air bleed elevates idle till warm . You can feel strong vacuum in the square port inside throttle body. When warmed up you shouldn't feel vacuum. It is common to get gunked up . Try spraying cleaner in the port. Also coolant passes thru it so if thermostat isn't opening that could also cause the problem as well.