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
  1. Home
  2. Questions
  3. 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: Car is showing random misfire code po300

The only sensor that will cause the RPM gauge to read incorrectly and cause a rough running engine is the crankshaft position sensor, or its wiring and connector. Try and disconnect the crankshaft sensor connector located above the oil filter...

Q: Crank no start. Not switching signals at the ignition coil.

Hi there. When your friend removed the spark plug while the engine was running and it was not grounded, the lazy spark may have shorted out the module in the distributor or it could have shorted out the coil in...

Q: Can I switch from Synthec oil back to conventional oil?

When you go to have your oil changed next time you can change to conventional oil without any problems. You can have a mobile mechanic like one from YourMechanic come to your location and the oil change for you. The...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
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...
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...