I have a '94 GT Convertible. When I am driving, the car acts like it does not want to go above 1500 RPM. It's almost like the car finds it difficult to go above 1500 unless I'm on it pretty hard. The car isn't running rough or anything, it just acts like it doesn't want to go above 1500 RPM and I have absolutely no idea what could be causing it. Any help would be greatly appreciated.