Chevrolet: 1998 Chevy Cavalier, chevy cavalier, rad cap

Question
My car is overhaeting. I changed the water pump due to leaking. Now it wants to overheat while idling. When I rev the engine, it will drop back down. What could be wrong?

Answer
Vickie ;
H - I would check the belt to see if it is tight enough or it might be sliping, also are the hoses all good, and is the thermastat old. and do you have enough coolent in it. also how is the rad. cap.   it might be that the belt is slipping ? you say it cools down if you give it gas , so check the above.