1999 Corolla Idle Speed Control Problem.

[Bill...]

Hi Guys. I have a problem with my 1999 Corolla with 4AFE engine. The details, and hopefully clues... When it is cold it runs well. When it warms up the idle goes up to about 1500rpm. When I throttle off for a gear change the revs stay up for a second or two. When it is cruising on light throttle and probably using the idle fuel valve it runs roughly - fine as soon as I give it some more gas. I pulled the Idle Speed Control valve off and cleaned it, put it back etc and it ran well until it got to operating temps in a few minutes. I replaced the complete throttle body and ISC vavle with a replacement one from a wreaker. The problems are exactly the same. I looked for vacume leaks and didn't find any. Any ideas? Thanks, Bill.

[Stick 21]

It sounds like the engine temperature switch to me, it may be causing the automatic choke to stay on after engine has warmed up, its located underneath the distributor or coil pack probably in your case as it is 1999, it has 2 wires coming from it, just plug it out and see does it make a difference. if it does then thats the problem.

[Bill...]

Thanks Stick. I'll try that. All the best, Bill.