Okay,

I got the new thermostat in, but I have a problem. Since I did the this, my idle has been screwy. It normally sits around 700-800 RPM, but every so often, it kicks up to 1800-1900 or so for about 20-30 seconds, and then goes back down to normal.

My guesses are:

1. I stretched a belt during the install, and it is slipping, letting the idle go high.

2. I knocked something loose by accident (vacuum hose maybe).

3. I didn't burp the cooling system well enough, and their is an air pocket.

Which one of these is most likely to cause the problem I am having?

Thanks