My temp gauge wasnt working for about a week, i was driving to work and noticed it was moving just as i got into the freeway, when i shifted into second the temp gauge started moving i thought it justed started to work cuz it was trying to tell me my car was overheating so i pulled over as i let off the gas it went down, so i parked and it went all the way down so i got back into the freeway and it started to move as if it was the rpm but not smoothly kind of shaking Can someone help me out. BTW i drive a 90 Civic Si.

 

Check the wire connection for temp sensor. May be when you hit a bump it shuts off. When bump it again it reads. May be loose connection or wire itself is not connected to female connector