What Are the Signs That My Spark Plugs Are Going Bad?

Detonation. That is what the spark plugs do. Air and fuel are mixed in the cylinders and the spark plug detonates or sets that mixture on fire. Without spark plugs, your engine cannot start or run because there will be no detonation or engine combustion. Changing the spark plugs can be confusing; some people say every 30,000 miles while others say every 100,000 miles. Automotive Specialists, Inc., lists the signs that your spark plugs are going bad below so that you know when they must be changed.

Acceleration Problems

Your vehicle requires a spark each time you press down on the accelerator. This gives the engine the power it needs to get up and go. If the spark plugs are worn, you might notice that your acceleration is sluggish or completely non-responsive.

Bad Gas Mileage

The spark plugs help your engine burn gasoline efficiently, so it makes sense that if they’re going bad, your gas mileage will suffer. Worn spark plugs make the engine work harder to get up to and maintain speed. Consequently, the engine will burn more gas.

Engine Misfiring

If you hear intermittent stuttering or sputtering sounds coming from the engine, it’s probably the spark plugs misfiring. Worn plugs and plug wires will misfire, but the problem could also be in your engine control module, the computer chip responsible for firing the spark plugs.

Engine Performance Trouble

Other signs of spark plug problems include your engine hesitating (even after you’ve accelerated) or surging. Hesitation points to worn spark plugs or plug wires. Surging could mean you’ve got too much air in the engine that is causing the plugs to misfire or fire too often.

Rough Idling

You might hear the bad spark plugs misfire and feel your automobile vibrate while you’re sitting at an idle. You may fear that your engine is going to stall, so you give it a little gas to prevent that from happening. Your idling should be smooth. Rough idles could mean spark plug problems.


Finally, if your spark plugs are really worn out, your engine may, indeed, stall. It might also get harder and harder to get it started each time you turn the key in the ignition. Again, the engine cannot begin to produce combustion without detonation, so your spark plugs could be to blame.

The best auto service shop in Westminster, CO, Automotive Specialists, Inc., will get to the bottom of your engine performance and gas mileage issues, even if it is the spark plugs.

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