whats wrong w my car?

What about the cooling fan, is it working?

You could have a bad head gasket. If combustion gases are getting into the cooling system this could over pressurize the cooling system and mimic an overheating problem.

Have you changed the water pump?

Check that the lower radiator hose is not colapsing when engine RPM's are up. Open hood hold throtle by hand and watch hose

check your thermstat in a glass of hot water to see if it working.....i had to change about 4 on my car because they were all faulty!