I'm having a very confusing problem with the temperature gauge in my 5-spd 95 Integra sedan. Once the car is at normal operating temperature, and I go from 1/2 to wide open throttle, the temp gauge drops down to cold abruptly. (Ex. If I'm passing someone on a two lane highway) Once I let off the throttle and bring the car to cruising speed again, the temperature gauge returns to its normal reading of about halfway between hot and cold. I'm not sure if it is the gauge itself, the coolant temperature sensor having resistance issues, or if it has something to do with the engine thermostat. If anyone has had similar problems, or might know the solution to this problem, feel free to share your insight.

 

Check coolant level, if you haven't already.

I'm thinking thermostat.

 

Me too. Sounds like it is stuck open.

A new thermostat is $13 from Honda and it takes 10 minutes to replace.

 

Another symptom of a stuck thermostat would be that it takes a REALLY long time for the motor to warm up. Take that into consideration as well.

 

Or unplug that plug and get it cleaned out. All it is is a single wire plug under your distro check it and make sure it's nice and clean free of rust and crap.