Hello everyone! I am new to this forum, but I need your help. I have a 91 RS, with 39,000 miles on it. It is my weekend cruiser, that I take out every couple of months. Anyway, I had it out about a month ago, and was cruising around when my check engine light came on. The next thing I knew, my engine temp. was hitting 230 degrees, and I had absolutely no power. I turned the car around, and started for the house so I wouldn't cook it, and then the check engine light went out, temp. dropped and all the power came back. This happened twice in the same day, so I took it to the chevrolet shop and they had it for a week and couldn't find anything. I took it out again last weekend, and it did the same thing as long as I was going 70 mph. If a backed off to 60 mph, it ran like a champ, and drove it around for about 3 hours. I have a new thermostat, checked my electric fans, and they are working fine. Any help that you all could be would be greatly appreciated.

 

Did the Chevrolet shop tell you what, if any, error codes were stored? Just because the light went away doesn't mean the code, or the problem did.
Here's how to read the codes: http://www.troublecodes.net/GM/
Note: your car will show a code 12 (no distributor signal) because the engine is not running. And each error code will flash three times, then go on to the next.

 

They told me that there was a code for running lean, but I don't remember what it was. They also told me, that they cleared it.