On my 91 pickup with 22re eng, it takes a very long time to come down to a normal idle. The colder the longer. What controls this and is it adjustable or replaceable?

 

There is a valve that controls the cold high idle. It's purely mechanical. It has a vacuum line and two small coolant lines going to it, and inside it has a bimetal leaf that opens or closes off the vacuum line. When cold, the bimetal is open creating a vacuum leak. When it runs a couple of minutes the coolant starts to heat up and the bimetal closes off the vacuum leak and the idle returns to normal. This of course would take longer when cold. On my 22RE this valve went bad after 7 years or so (I didn't have any high idle when cold) so eventually (I left it this way for a year or two - no problems) I took it apart and opened it up to see how it worked. Turns out it can be adjusted. There is a set screw that pre-tensions the bimetal. So I made an adjustment, reinstalled it, tried it again the next morning, took it out, made an adjustment, tried it again the next morning. Got it spot on and it was good for another couple of years. I readjusted it.... Or you can buy a $60 part and put it in... It's easy to get to and easy to adjust if you don't mind dinking around with it.

Sorry, can't post a pic and can't tell you which way the adjustments worked - it was long ago and I don't have a 22RE handy to look at and take a pic. I can tell you that I made like 1/6th turn adjustments at a time, a little made a big difference.