Skip the auto shop - Our mechanics make house calls

Q: The vehicle is jerking and not firing and the plug number 4 is soaked with oil.

asked by on

I started my car last weekend and drove it. After, about 5 minutes, it started jerking very badly and it wasn't firing. There was no fault indication on the screen. I have run a diagnostic test and it didn't reveal anything. My mechanic checked the plugs and discovered that the plug number 4 is soaked in oil. The vehicle is still jerking and that plug is still oil soaked. Even when we replaced the plug, it still had the same problem.

My car has 19000 miles.
My car has an automatic transmission.

Hi there. When a spark plug has excessive oil on the plug, then there is excessive oil getting into the cylinder. This will foul out the spark plug and cause a misfire. The misfire is causing the engine to be jerky. There are three areas that cause excessive oil in the cylinder.

  • The oil scraper rings on the piston is worn and causing the oil to not crape down off the cylinder wall.
  • The Positive Crankcase Ventilation Valve (PCV) is plugged up causing the crankcase to over pressurize forcing the oil into the cylinder.
  • The valve guide seal on the intake valve is split or damaged causing oil to puddle up on the intake valve and being sucked in on the intake stroke.

Check the above areas and one of them will be the cause and repair to your symptom. If you need further assistance with your engine having excessive oil on the spark plugs, then seek out a professional, such as one from Your Mechanic, to help 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
  • Home
  • Questions
  • The vehicle is jerking and not firing and the plug number 4 is soaked with oil.

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: Where is the camshaft position bank 1 sensor A at?

The sensor is at the front right top of the engine beneath the large plastic engine cover. It is held on by a single T-30 torx bit machine screw. Please note that OBD-II diagnostic trouble codes, such as the code...

Q: I have a 2004 GMC Sierra 1505.3 V-8 what’s a long lasting to Portland for the truck

The spark plugs from the factory are AC R41-985 and can come in Iridium or Platinum tip spark plugs. Both of these plugs are designed to last up to 100,000 miles. There are other spark plug brands and may be...

Q: My car did not start and the dash said oil reset inspection.

Hi there. The message is on for the computer (ECM) has lost its memory for the engine oil timer. Billing question was sent to CS for the cost of resetting the engine oil timer programming in the ECM on a...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...
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.