I need help with my cylinder misfire

just got a used Hyundai 2001 accent it has 59k miles and the computer is saying there is a cylinder 3 misfire I have replaced the plugs and the code is still there while replacing the plugs there was a small pole of oil or carbon build up under the spark plug socket do you guys have any idea of what i should try next??

Does a 2001 Hyundai have a coil on plug style ignition or individual plug wires?

If coil on plug style, I’d swap the coil on the misfiring cylinder with a coil from another cylinder and see if the misfire moves.

If it has plug wires, check them and make sure they’re in good shape and seated well on the plug and on the coil.

That would be where I’d start. Does the plug with the misfiring cylinder have a strong gas smell?

Looks like that model car has coil packs, so will have plug wires. Need to check those for obvious damage.

May not be your issue. You mentioned oil on the spark plug socket. Where was the oil exactly? Pooling around the plug in the plug well?

i pulled out the spark plug and the socket is at a slight angle so just below the spark plug there was some oil and the plug wires had some on it as well

Did you have an oil change recently? They could have spilled some oil while filling it with fresh oil.
Your valve cover gasket could be leaking around the spark plug holes.Try tightening it or get a new one.

now that you bring that up maybe i had just purchased the car from a private dealer oh about a week ago and the last oil change was a few days before i bought it and the valve cover was covered in a film of old oil that could be what that is from.

Because you have “coil packs and plug wires” on this model the oil could be causing the plug wires to arc to the valve cover or head, etc…

I would use a can of “Brake Clean” to spray that oil away and dry the plug wires. Wait 20 minutes for all the fumes to dissipate and then start the engine. If you plan this so that it is dark when you start the engine, you should be able to see the plug wires arcing if that is the problem.

Then you should look carefully to find if there is leaking oil somewhere.


When you got a misfire on a particular cylinder the easiest way to diagnose it usually is to swap stuff between that cylinder and one you know works. If after a swap the misfire moves to the other cylinder, you got it diagnosed. What order you decide to try is up to you, but the obvious suspects are

  • spark plugs
  • spark plug wires
  • coils (if cops technology)
  • fuel injectors

If none of those work, a compression check is up next.

If you feel the no 3 spark plug isn’t seating correctly, probably best to have an auto machine shop give it a look-see.

OK problem solved i went and pulled the fuel rail off and cleaned all the injectors and rail and stuck some di electric grease into all the electrical fittings now the oll gal running like it just came out of the dealer ship