Spark Plugs Service Video

Spark plugs ignite the air-fuel mixture in each engine cylinder. This video compares a worn spark plug with a new one and explains why the electrode gap widens over time. It also shows how spark plug wear affects your vehicle's performance.

Most gasoline engines use four to eight spark plugs that fire thousands of times per minute. Even one worn spark plug can force its ignition coil to work harder to produce a spark across the gap. Drivers who commute daily on I-55 or run errands across Kingshighway tend to notice the symptoms first at highway speed, where the engine is under sustained load.

Each spark plug threads into the cylinder head, with its electrode exposed to the combustion chamber. Every ignition cycle erodes a tiny amount of metal from the electrode tip. Over 60,000 to 100,000 miles, the spark plug gap gradually widens until the ignition coil can no longer produce a consistent spark. The cylinder may start misfiring under load before the problem becomes noticeable at idle.

Iridium and platinum spark plugs last longer than copper plugs because their electrodes resist erosion at higher temperatures. Choosing the right spark plug type for your engine's design is also important for reliable performance.

Common warning signs include a rough idle, hesitation during acceleration, a check engine light with a P0300-series misfire code, and reduced fuel economy. Ignoring these symptoms can eventually damage the catalytic converter as unburned fuel enters the exhaust system. Short-trip driving through Jackson and Scott City, where the engine never fully reaches operating temperature, leaves carbon deposits on the plug tips that accelerate erosion. If the misfire code is already stored, the next step is check engine light diagnostics to confirm which cylinder is failing before the plugs come out.

At Parks Automotive, we start spark plug replacement by reading fault codes and inspecting each plug for signs of wear. We then compare the wear patterns with the engine's fuel trim and ignition data to identify potential problems. Fouled plugs, oil-wet plugs, and plugs with cracked porcelain can each indicate a different underlying problem. Replacing them without identifying the cause may cause the new plugs to foul within months.

Spark plug replacement is part of our broader engine diagnostic services. We torque every spark plug to the manufacturer's specifications and apply anti-seize only when the plug design requires it. Over-torqued plugs strip aluminum cylinder heads, and no customer wants to hear about that.

Call Parks Automotive at (573) 335-2599 to have your spark plugs checked, or find a local mechanic in Cape Girardeau County online. Drivers from Cape Girardeau, Jackson, and Scott City have us handle the job as part of routine tune-up service.