Well my car has been doin this the past few days. When my car is warm and im sitting at a light right when i stop the gauge is normal, a little before halfway, then about 5 seconds later my needle raises to about 3/4 and right when i start to move the gauge drops to normal? coolant levels are good and everything

 

you sure you dont have a vaccume leaks?

 

You may have air in the system. Bleed the coolant system. Do your fans come on at all?

 

Has your car overheated at all lately? And you said you have not had to add any fluid to it?

 

no it hasnt overheated and everything has been running normal...it seems to do it more when im doin stop/go city driving

 

Well, I was having a similar problem with mine, and it turned out I had a leaking hose. Without proper pressure to the system your fluid is not going to circulate, causing your overheating problems. The reason it would not be rising while driving is because you've got cool air entering into your engine bay to help regulate the temp of the engine

 

He said on AIM his fans don't turn on. Check the thermostat and fan relays.