Skip the auto shop - Our mechanics make house calls

Q: Piston misfiring and oil on a sparkplug

asked by on

My car has a misfire on the 4th piston. I wanted to fix this myself so I replaced the sparkplugs. I found oil on a sparkplug. What caused this? Please give me some advice on what to check and fix the issue.

Oil in the spark plug bore is caused by a leaking valve cover gasket. This can short out the spark plug and cause damage to the plug and coil, and also the spark plug boot. The valve cover gasket set needs to be replaced to correct the issue. You may want to enlist the help of a mechanic, such as one from YourMechanic, who will have the tools and training to replace the valve cover gasket for you.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Water leak in my rear passenger foot well

There may be no easy answer for this. Modern cars are so thoroughly insulated and sealed, and the interior structures are so complex that it can be very difficult to find the kind of leak that you're looking for. It...

Q: Incorrect spark plug replacement caused worse gas mileage

Hello there, thank you for asking about your 1997 Oldsmobile LSS. AC Delco 41101 comes standard on these vehicles and must be used in order to maintain the ignition system properly. Also, find a maintenance schedule for the vehicle and...

Q: Brake Pads replacement Alert

Hi there. There are several different types of brake pads available for your vehicle. These all range in price/quality and generally, but not always, the higher price is usually the better product. You can rest assured that a technician from...

Related articles

P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.