Brad10071977 & MassContour:
If you look at the strategy the PCM uses to turn the cooling fans on, that kind of fluctuation of the temp gauge is normal when driving in stop and go traffic, on a hot day, while doing a lot of idling. If you're out in the open, on a hot day (90+ deg F), tooling along at over 35-40 MPH, I'd say that temps higher than the "R" on the gauge MIGHT be cause for concern. If it's over 100 deg F outside, you just might expect to see readings close to mid scale while cruising along.
This all assumes you have a stock 'stat and normal PCM programming. Guy's like Demon with 160 deg 'stats and tweeked PCMs will prolly read lower on the gauge. If the car's sitting still and the fans aren't running, there ain't a hell of a lot of cooling going on.
As I said before, if your cooling system's healthy, the A/C's on and the low speed fan circuit is functioning properly, you'll prolly see lower temps and less fluctuation because the fans are running on at least low all the time.
