Ok, if I'm going down the road in 4th or 5th gear (probably around 50 mph) the car will start to jump some and act like i'm letting off and on the gas. It finally irritated me enough to where i pushed the gas to the floor while it was doing it. Nothing happened at all. Did rev up or anything, it just sat there for a few seconds and then revved up.. If I push the clutch in and rev it its fine. Any ideas?