1996 Pontiac Firebird

The guage goes up but the car not overheating. This could be a couple of things. I could be that the thermastat is going bad, the radiator is obstructed so air is not going through it cooling the coolant, circulating problem, or that the temp sending unit is going bad or that there the wire going to the temp sending unit is touching somewhere. I would start with the air circulating throught the radiator, then work to the sending unit. If there is a rapid fluciating in the temp then that is a sign of lack of coolant or the therrmastat is sticking