I have an 87 lg4 original carb and i took my coolant temperature sensor to put a aftermarket gauge in. After about two weeks the idel shot up to 2500 rpm and wouldnt idel down. After messing with my idel screws anything below1500 it would kill. So i put the sensor back in and now it wont start on a cold start at all. I have to take the plug off the sensor to crank it. Any help????

 

You mean the coolant temp sensor over on the driver's side head between plug #1 and #3? Should have nothing to do with your carb at all, if that's the case.

 

there are 2 sensors I'm sure he means the one in the intake plenum. install a new one they are fragile, and make sure the pins are not bent over.

 

Why did you put an aftermarket gauge in? Is the factory one broken?

Where exactly, on your engine, is the sensor you replaced?