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

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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.

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