I have a 93 5.7 that I swapped to a 6.5. I am having an issue with the coolant temp indicator. The ect sensor is new. On start up the indicator reads cold, and after about a minute of Idle the temp begins to come up. Once the needle reaches the area of the guage that has some numbers, the needle quickly pegs completely hot. The engine is still pretty cold, and the resistance of the ect sensor is maybe around 800-1000 ohms when I have checked it. If I unplug it the guage pegs cold again. If I short the green wire to ground, the sensor of course pegs hot. I have replaced the cluster with a junkyard unit and still have the exact same problem. I have pulled apart the cluster, and traced the circuit. There is a 10 ohm resistor (by code) that is accurate on the small pcb with the logic chips on it. And there is no break or excessive resisistance in the traces to the guage. I have pulled the cluster, and directly hooked up power and ground to their pegs, and a jumper from the ect sensor to the S peg on the back of the guage. when I started the vehicle, I had the exact same symptom. Can anyone tell me what I am missing?