MY FP Gauge has stopped returning to zero after the engine shuts down. The readings while running seem true - 16 @ idle, 13 @ WOT. Should I be concerned? Is there a way to correct this issue?

 

Electric or mechanical gauge?
If you have an isolator they often cause this type of problem, ditch it.

 

A gauge that doesn't read correctly ALL the time is worse than no gauge at all. An incorrect reading can lead to a false sense of security while no gauge means you are always on guard. If you tap the gauge lightly does it then return to zero? If so it's the actual gauge, if it has an isolator like infidel says that could be the problem.

 

It's mechanical. Antifreeze from the sensor to the gauge. When I tap it it does not move. Where is the isolator and how do I remove it? The readings when running are accurate and haven't changed in the 3+ years since installed.

 

check to make sure that the antifreeze hasnt leaked out, mine leaked around the fitting on the isolater. had this happen to me once but i discovered it after i had bought a new isolater and went to install it.

i placed my isolater on the firewall above and behind the brake cylinder.

 

To follow up: I unscrewed the connection and allowed a small amount of antifreeze to drain out. Reconnected and started the engine. All numbers back to normal and the gauge reads "0" when the engine is off. I may have overfilled the system the last time I added antifreeze. Thanks for the suggestions.