Quote Originally Posted by Z U L8R
then replace the coolant temp sending unit. that's what gives the guage it's resistance. the coolant temp sensor tells the ecu the car is warm or cold so it can adjust fuel trim. if you've isolated the problem to just a faulty reading then start with the sending unit, it's cheap. you don't need the sensor i was just mentioning it so you don't get the two confused
Listen to this man.

If your Laser Temp gun is only registering 180 degrees, but your cluster is pegging hot, check ALL YOUR GROUNDS, and replace the thermostat and Coolant temp SEnding unit switch thingy, its on the side of the head.