1991 Buick Regal, 3800 V6
As the title says, when I start the engine cold I get a slight puttering and drop in RPMs followed by the engine revving itself to about 1100 for a few seconds and then normalizing at 600. It has only actually stalled out a few times. This does not happen once the engine is near operating temperature.
Now, I did not notice this issue prior to doing some maintenance on the vehicle (radiator replacement and transmission service) and I’ve read that this can be caused by a faulty coolant sensor. Possible?
Battery is new.
Also, when I say cold start I mean summer temps here in Michigan. So it’s happening anywhere from 50 to 90 degrees F.