I have a friend that has a 90 Cavalier Z24 with a 3.1 engine. He has a couple of problems with the car.One is that he can be driving it and suddenly he loses power and the motor starts to labour. The second is that he can pull up to a stop sign,be sitting there and suddenly the motor will rev up by itself. So far he has replaced gas cap,fuel filter,O2 sensor (twice),throttle position sensor,and tried another used computer in it.Does anyone have any other suggestions? I have not taken the car out for a spin myself but those are the way he describes the problem's.