Just got a 97 lt1 fbody, manual, w/67K miles. No SES or codes and seems to run fine. Often, when started cold the idle is fine until I drive over 10mph. When slowing down, the idle stays at about 2Krpm until about 5mph, and then the idle drops. After warm up (180 deg) and restarting car (70deg outside temp), the temp gauge shows about 210deg until I get moving quicker than about 30mph, but the idle works fine. Any ideas?

 

maybe when the car is cold the throttle plates are sticking since metal contracts when cold and expands when hot ??? Other than that not sure. I do know that mine idles great in open loop but when it goes into closed and its cold out it sometimes bumps the idle up a little bit. Dont know why tho .