My temp gauge was fine. I cranked the car and it spiked during cranking which is normal. It just never came back down and is stuck. I tapped the gauge and it fell back down. I put key forwarded. Was still fine. I cranked car and the same thing happened and it stuck maxed out. From what I've read here. If the sending unit is bad, or the wire is grounded. It will cause it to stay spiked. But since it went back down and I put the key forward and it still was fine. Tells me that the sending unit and wiring is ok. It just seems to get stuck when cranking.

Anyway. Do all these aftermarket gauges have to run off there own sending units? If so, is there one that will fit where the stock sending unit is now?