My Yota has developed a crazy idle problem. When I start it up it idles way to high, then after a minute or two it settles down. Then after a few minutes it starts idllng really high, then goes into an up and down idle. Then I noticed when the temp on the gauge hits normal operating temperature it settles down and idles normal. It does so until the next morning. It's always on a cold start. Any ideas?

 

The looping idle sounds like a vacuum leak. I'd start check all the vac lines, and the air flow plumbing for cracks and such.

 

x2 on checking for vac leaks..

are you low on coolant?

 

Done that. Usually vac leaks makes it idle high, with a little erratic idle. This is a off idle to 2500 rpm idle, up and down, very fast. And like I said it completely stops after it warms up.

Maybe I need to do a sound file.

 

That is the fuel regulator killing the fuel. They do that if your idle is to high (Vac leak) in open loop. Your idle contact in the TPS is closed and your idle is above 1100RPM hence the bouncing. Correct the idle.

If you have air in your cooling system it will cause the idle up mechanism (coolent operated) to think that the engine is cold thus a high idle. Check that your coolent is full and no air in it.

 

Couldn't hurt to check the coolant temp switch, either

 

at least make sure the throttle position sensor is set properly.

 

x2 on air in the cooling system