my temp gauge on my cluster in my 96 SS flicks up and down very fast. Its very strange it reads the correct temp for a second, then flicks up and down at random. Almost every time my foot is on the brake it is pinned to hot and the hot temp lamp comes on, then immediately when i take my foot off the brake it goes back to normal then flicking like crazy. also it only does this in drive, if im at a stop light, and shift into neutral, the temp gauge reads normal, and will not flick. How can i test for a good or bad sensor/wiring ?