I have a temperataure gauge in an 82 Firebird that has started to vary. It used to stay steady below 220 but now it varies into the red and out again. It will settle down after about an hour of driving. I checked the engine and that is not overheating, reading just under 200 degrees. I have replaced the sender and the temp gauge but that didn't stop it.

I was wondering were is the voltage regulator on these cars. Is there a regulator on each gauge or just one for all the gauges. maybe that's gone faulty but none of the other gauges vary.

Anyone any suggestions as to what the problem might be.

Thanks.