High idle after removing & throttle body 99 Century

[lewie2792]

Greetings:
I removed the throttle body on the 3.1 to get to the thermostat housing. Reassembled and made sure the sensor connectors were all reconnected. First time the engine idled very low, almost stalling. Removed again to check and reassembled. Now it idles very high.
Before all this there was no problem with the idle. Of course, it must be something I did when removing the throttle body.
Would a bad or missing gasket cause this kind of problem? I have the Haynes book and thought of checking idle air control but the book does not state whether to check olms on the pins on the idle air control valve or the connector. I did not replace the throttle body gasket.

Any suggestions would be appreciated! I will post results.

Thanks!!

John

 

[Spriteman]

Make sure the IAC has a good connection with the connector.

Ensure all vacuum hoses/tubes have been reattached.

 

[Fieromaster]

If you didn't replace the Throttle body gasket when you did the work, it probably has a Vacuum leak now, which causes high idle. I'd start by replacing the gasket first. When you do it though, make sure that you scuff the surfaces with a green scratcher pad or similar to get a really clean mating surface.

-Mitch

 

[lewie2792]

Thank you for the replies! As promised, I am reporting results. I again disassembled all from the air filter box to and including the throttle body. I used throttle body cleaner on the body and the idle air sensor pin. I very carefully reassembled all and was very careful with the hoses connecting to the air filter box. Throttle body gasket was in very good shape. I can only guess that I may not have tightened throttle body completely or did not get one of the air hose (especially the one connecting to the air filter box) snug on the lip.
She runs fine now. Very slight stumbling at idle when cold....after that fine.
Again, thanks for the suggestions.
Regards, John