What causes an engine to vibrate at rough idle?
What causes an engine to vibrate at rough idle? It only takes a minor problem like a fouled spark plug to cause your engine to vibrate. Idle problems may originate in a worn out component, a failed part, or a blown gasket. The number of potential sources of a rough idle can make your diagnostic a little difficult. Why does my car idle when out of time? An engine slightly out of time can idle roughly since the spark is not in sync with the cylinders. Too much timing advance or retardation causes serious drivability problems. Many problems may upset...