Sounds like the problem I had with F1 2002, then GP4, then GPL...
What controler are you using? It's like the kind of problem I had, and it happened becasue I was using a Gameport Joystick, not USB. It might only happen with higher FPS now, but it will eventually get worse and become unplayable if this is the problem I had. It has little to do with your FPS really.