Can You Still Drive with a Faulty Spark Plug?
3 Answers
You can still drive for a short period with a faulty spark plug, but it's not advisable in the long run. A faulty spark plug not only causes unstable ignition but may also lead to failure to start. Additionally, once a spark plug is damaged, it's equivalent to losing one cylinder's operation, resulting in noticeable engine vibration and reduced power. In severe cases, it may even cause electrical leakage. Commonly known as a sparking plug, the spark plug's function is to discharge the high-voltage pulse electricity sent by the high-voltage wire (spark plug wire), breaking down the air between the two electrodes to generate an electric spark, thereby igniting the mixed gas in the cylinder.
I've been driving for decades, and this is something you really can't take lightly. If the spark plugs go bad, the car can still run, but it shakes like a tractor, lacks power when you step on the gas, and fuel consumption skyrockets. If one cylinder fails, you might barely make it home, but if all four give out, the engine could stall anytime—breaking down on an overpass is downright dangerous. I've experienced cases where the ignition coils got fried along with it, costing me over 800 bucks extra in repairs. It's really better to address it early. Keeping a set of emergency spark plugs in the car is quite practical—replacing them yourself takes just ten minutes. If you feel the engine struggling badly during acceleration, pull over immediately; calling a tow truck is much cheaper than repairing the engine.
My experience is, never push it when the spark plugs are failing. I tried to start the car when it was having ignition difficulties, and the exhaust pipe emitted black smoke, causing the emissions test to fail directly. The mechanic said prolonged use like this can lead to carbon buildup, and even the piston rings could wear out. Especially for direct injection engines, spark plugs operate at high temperatures, and if they fail, they can easily damage the catalytic converter, which would cost thousands to replace. Driving short distances of three to five kilometers in an emergency is acceptable, but keep the RPM below 2000. It's best to go to a professional shop immediately. Nowadays, platinum spark plugs can be replaced for just over a hundred, which is more cost-effective than paying for a tow truck.
