Those 40,000 volts cause the spark plug to emit a spark and light up the air/fuel mixture. However, if these little plugs become contaminated by oil, they can malfunction, or worse.

How long spark plugs last varies with different cars and different types of spark plugs. Older cars often had to have their spark plugs replaced every 5,000 to 10,000 miles, while some newer cars ...

Experts recommend that spark plug cables should be replaced every 30,000 to 70,000 miles, with some lasting up to 100,000 miles. While that is a pretty broad range, there are a few telltale signs ...

If your car is older, if and when you need to change your spark plugs will largely depend on how your car is behaving. If a car has a bad spark plug, it'll usually let you know pretty quickly.

Because spark plug sockets are just slightly different versions of regular sockets, they're not astronomically expensive tools. Gearwrench will sell you one for just over $10 on Amazon.

Our Verdict For a high-quality spark plug, consider the NGK 6619 Iridium IX Spark Plugs, featuring excellent performance, power, efficiency, and reliability. Or, choose the Denso 4504 PK20TT ...

Alternatively, you can use a spark plug light. However, this only shows if a signal is being sent to generate a spark and not that the plug is, in fact, firing.

Spark-plug heat ranges should stay the same as at sea level, unless racing above 3,000 feet, where one step hotter usually suffices. 10.

How To Tell If Your Spark Plug Cables Need Replacing If you're unsure of whether or not your vehicle's spark plug wires need replacing, and you don't want to bring it into a mechanic for servicing ...