Hello everyone so I have an 1989 iroc z 350 tpi I just put headers on it And did an oil change did the wires n the spark pluges after I was done with everything I started It up n let it run for a bit. The temp gauge in the car didn't move I double checked the coolant temp sensor under the throttle body n it was plugged in so I have no idea what it could b can anyone help me. Thanks so much.

 

The temperature sensor you looked at is one of the things that tells the computer when to go into closed loop mode. Look at the drivers side head, between the #1 and #3 cylinders for the temperature (gauge) sending unit. You probably broke or knocked the wire off while doing the header install.

 

should be a single wire plug, possibly/probably dark green