I have Googled and searched for an answer and I am left with two options. The problem is when I bought this 86 GT the temp gauge did not read anything. I did the usual tests pulling the wire off the sender and grounding it out and watching the gauge swing one way then the other. I replaced the sender and used teflon tape the first time. Dumb move. The gauge was reading but it was up under the L in NORMAL and even higher. After I read that I cleaned the tape off and it still does the same thing. I used my infrared temp gun and all around the water neck, intake and radiator it's reading around 180*. Certainly not off the charts. I tested the senders resistance with a meter and probed the top and bottom of the sender as well as the top and the motor and they both gave me about the same readings. I also probed the top of the meter to the ground side of the battery and that gave me a totally different reading. All my other gauges read correctly except for the volt gauge and they never work I see. Do I have a bad engine to chassis ground, need some sort of resistor in my gauge cluster or try another sender?