depends what kind of knocking sound, does it knock all the time when the engine is running or does it taper off as the engine runs. does it sound like a tapping sound or a deep knock. if it sounds like a knocking sound when you press the gas pedal under load it could be timing, if it is a tapping sound that quiets down when the engine runs it could be lifters, if it is a constant knocking sound that continues when the engine runs it could be a rod or piston. if its a constant knocking sound you might have to rebuild the engine.
Jan 15, 2008 at 7:37 AM