My 86 temp gauge has started going crazy. It shows 100 most of the time with the occasional trip to 220 or pegged out. It grounds when cranking and I've had 2 new sensors in it and still the same thing. Sometimes it will seem to work right and then it'll start twitching. What else could cause this ? Thanks

 

check your wires go to the sensor from the gauge. make sure there are no cracks or split that could cause it to short out. i was having the same problem and my issue was the wires that where actually plugging into the sensor had a back connection. so i had to pull the wires out of the plug and just touch them to the sensor. i wouldn't recommend doing it that way if that is what the problem is, but these are just some tips. mine works perfect now though

 

No cracks, it goes back into a big harness and its a little green wire. I cut the plug in off and just wrapped the wire around it and still does the same thing. It seems as if it works more accuarately when you turn the car off. Like it could be pegged out running and when you kill the engine it goes to a quarter of the gauge but when you turn teh key back on it goes crazy again, I'm starting the think the gauge is just bad.Thanks