What will a bad spark plug look like?

You can visually inspect the spark plug wires and spark plug to look for any signs of corrosion or damage. If all of the spark plug wires look fine, it's possible that there is an issue with the spark plug itself. You can quickly and easily check for a bad spark plug by removing it. Just be careful not to lose any of the individual spark plug wires.

What will a

If you notice the spark plug is black and appears to have a shiny, metallic appearance, then you likely have carbon build up on the insulator and the electrode. These spark plugs are not very reliable as carbon tends to break off and cause internal damage. It is very important to have your spark plugs replaced at the first sign of an issue. If you notice any of the above issues, do not continue to drive your car until you have the spark plug replaced.

What will a spark plug look like if it's a bad head gasket?

If you have a missing or damaged spark plug head gasket, you can expect some odd engine noises and poor fuel mileage. You won’t be able to hold a spark under load, and you’ll definitely want to have your head gasket replaced.

What will a plug look like if it's a bad spark plug?

If you have a spark plug that sparks but doesn’t ignite your fuel, you may be able to fix the problem yourself. If you have a compression test kit, you can test the spark plug and determine if it’s actually a bad spark plug or not. If it doesn’t spark, then it’s most likely a bad plug and you should replace it as soon as possible.

What will a spark plug look like if it's a bad spark plug firing?

If you notice one or more of the spark plug electrodes is damaged, such as by corrosion, it will cause a poor spark. A spark plug that fails to ignite the air/fuel mixture will result in misfires and poor engine performance. If the spark plug fails to ignite the air/fuel mixture, it will cause a lean misfire condition. A lean misfire condition can also indicate a loose spark plug, faulty fuel delivery or even a faulty fuel injector.