My car is running rough. What’s causing it and what should I do?


This is not an easy answer. A rough running car can actually be caused by multiple issues. On late model cars, the most common causes are vacuum leaks due to a high number of plastic parts being used in the engine compartment, a weak or defective ignition coil, or a bad spark plug.

On any car neglecting a tune-up when necessary can cause an engine to run rough. Usually if this goes on for a while, the check engine light will turn on.

The best remedy is to have a certified technician scan the check engine light code to properly diagnose the exact cause. After that’s determined you’ll want to fix it ASAP. A reason for the urgency around fixing a rough running engine is that an extended duration can cause costly damage to your catalytic converter. This happens by unburned fuel reaching your converter.

When there is a presence of an extra rich fuel mixture, raw fuel enters the catalytic converter and is ignited. This can lead to melting of the catalytic converter.

Also, unnecessary heat can be created under the car which is dangerous if it’s parked on dry grass. In California that’s a real and present danger. Lastly, this situation can plug the catalytic converter after time. Bottom line: Please have your car seen if it’s running rough.