Hey All -- Looking for wisdom, as usual 87 K5 Silverado TBI 305 700R4 Np208 10bolt 90% stock I've got some wierdness going on with my temp gauge. After the truck has sat overnight and I turn the key to on, the temp gauge shows Cold (10 O'clock on the gauge). Then, without starting the motor, it gradually runs up to about 3/4 hot or so (1 o'clock) over about 30 seconds. If I then start the motor, it moves around a little erratically and jumps some and then pegs out after about 10 seconds on super hot (3 o'clock) about 1/4 about Full hot and stays there. I've put the mulitmeter on the sensor (while engine still warm) and gotten about 240 ohms resistance or so, and the sensor is getting about 5 volts to it with the key on and the motor off. So now the questions ... (1) Any thoughts?! (2) what is the normal resistance range of the sensor? (3) if the sensor circuit is open (sensor plug disconnected) (infinite resistance) will the gauge read cold or hot? (4) if the sensor circuit is grounded (zero resistance) will the gauge read hot or cold? (5) does this sound like a sensor, wiring, or gauge problem? Thanks for the help.