OK, this happened completely randomly, so I have no clue whats going down with it... Here is the lowdown, My car will start, once started it idles roughly between 500-750 RPM's. I press the gas pedal and nothing, RPM's may jump a little (50) but, its not very noticable. Then on top of that when I let out the clutch, a constant knocking occurs. Depress the clutch and knocking stops...Please help me with this! ANYONE!!!