Coolant Temp Sensor
 

If I leave the coolant temp sensor unplugged, so that the ecu does not see it, will I have issues starting my car? Ive seen others say that it can have issues, but i ran a sketchy plug that didn't really stay in for years and im wondering if i should redo the plug.

Are you speaking of the water thermosensor or the sensor which the temp gauge is connected to or ????

Are you referring to the coolant temp sensor behind the waterpump ? If so that sensor is critical for good engine operation. The ECU uses it as reference to "see" the engine temperature and determine the correct fuel mass to inject. Its probably also used for a bunch of other functions as well.

I swapped mine yesterday with a unit from the local auto parts store. It has a Denso equivalent part Nr and I made sure to test the resistance of both the new and the old sensor at around 12 deg C (3.6k Ohm) to make absolutely sure it will work. Its important.

Thanks, i realized its importanve when i looked into the ecu and saw that it determines calrabking fuel by temp. now i just need to fix my timing/starting issue.

If your having hot start issues and the sensor change didn't help, stop throwing parts at it and do a compression test with the engine warm