When I drive the temp is fine.

When I am at idle, the temp goes way up, as soon as I rev the engine to 2000+, its start to cool. As soon as I am back at idle, it starts to heat up.

What could this be?

How do I fix it?

 

i have a slightly larger issue..... my car overheats like a SOB no matter what i do.... i replaced the thermostat, and wired a switch to my fans to keep em on all the time while driving... and it STILL goes as much as 280 degrees.... now THATS a problem.... as for yours? im not so sure... you check ur thermostat? or do this, open your radiator cap and check how your cars water flow is.... sounds like it may be a water pump... when they start to go out they no longer have as much pressure to sustain a flow of coolant at an idle, so when u stomp on it, the motor increases the pressure of the pump, and cools it off.

 

Perform a pressure check on the cooling system. You may have a bad head gasket, or other leak in the system. Eliminate internal and external leaking as a problem.