surging idle

[82toyo]

I have a 1989 n/a and when it is cold the idle will surge up and down and after the car warms up it will stop surging and idle fine. Wondering if anyone else has had this problem or have an idea of what it might be. I have bled the coolant several times as someone told me that might be it but never changed the idle. Thanks for any help.

[gkcopperdrag]

Had this problem with my ford probe. Its called "Hunting" from what I was told. Never hurt the engine or anything.

[MR2Jedi]

most cars have an "idle up" valve that keeps RPMs up till it's warmed up. RPM's should lower to normal after the engine has warmed up.

[4DMR2t]

Yea, my '91 turbo does it all the time. Whenever I start it in the morning, it revs to like 2k, and slowly comes down, as it warms up.

My '97 RAV4 will actually bounce around for a while. It goes from 1k to 2k, down to 1.5k, back up to 2k, then finally settles at about 950 RPMs.

[johnr]

Check and adjust your speed control sensor, it should be located on your throttle body. Here check this out http://www.mr2-tech.com/bgb/mechanic..._system/16.htm I had the same problem. Fixed.

Originally Posted by 4DMR2t

Yea, my '91 turbo does it all the time. Whenever I start it in the morning, it revs to like 2k, and slowly comes down, as it warms up.

My '97 RAV4 will actually bounce around for a while. It goes from 1k to 2k, down to 1.5k, back up to 2k, then finally settles at about 950 RPMs.

[JekylandHyde]

The MKI MR2s have a tendecny to "hunt" at idle when the cooling system has air in it.
I suspect if you properly bleed your coolant system you will get rid of the hunting idle.
At the least, I would top the system off.

Good luck.

[ToyotaTechGeek]

i can't agree that it 'won't hurt anything'. fix that thing!