Very high idle

I searched the forum and did not come up with anything regarding this. I have a 99' Passport and it lately it has had a very high idle (2000-2500rpm's). I changed out the Idle control valve and it still does it. The thing is if I disconnect the battery and let it sit for a bit and hook it up, everything seems fine (a little high 1100-1200rpms). It will stay that way all day. The next day same thing happens again (2000-2500rpms). Anyone have any ideas?

Thanks in advance,
James

Throttle body is full of carbon or the intake manifold gasket is bad.

Throttle body is full of carbon or the intake manifold gasket is bad.

Thank you. I will look into that this weekend.

The idle-up switch on the power steering pump could also be stuck. Look for a small gray wire going to a fitting on the P-steering pump. Unhook that wire & see if the idle goes down. That idle up circuit is not needed.
G/luck
Joel

The idle-up switch on the power steering pump could also be stuck. Look for a small gray wire going to a fitting on the P-steering pump. Unhook that wire & see if the idle goes down. That idle up circuit is not needed.
G/luck
Joel

Thank you Joel. I will try that today.

I had this happen one day. Idle all of a sudden went up to 2000 or so. I stopped at the store I was going to, shut it down. When I was ready to go, all was back to normal. I cleaned the TB later that day, and it hasn't happened again...