I had a problem with my 04 civic. I took it in to have the timing belt and water pump done because I bought the car with 158k not knowing if it had ever been done. after getting the car back i noticed i did not warm up at idle. It has been really cold here so I figured that was it. after awhile I guessed maybe the thermostat had gone bad. I changed the thermostat with a stant brand replacement and everything went fine. I saw online that to bleed the system you are to loosen the ECT coolant sensor while running to purge the air. the second I unplugged it the check engine light came on and the idle increased. The check engine light is still on and it seems the idle is high. did I screw something up? and how do I fix it?

 

make sure its fully plugged in and clear the code

also get that Stant out and put a Honda thermostat back in