What Causes Rough Idling - If the ignition timing is off, the engine may struggle to run smoothly at idle. Apart from a bad spark plug, a cracked distributor cap or defective ignition coil could also cause rough idling. Incorrect ignition timing can cause rough idling.
If the ignition timing is off, the engine may struggle to run smoothly at idle. Incorrect ignition timing can cause rough idling. Apart from a bad spark plug, a cracked distributor cap or defective ignition coil could also cause rough idling.