Misfire/Oil In Spark Plug Well

My #4 cylinder started to misfire a few days ago, so I decided to replace the spark plugs. When replacing the spark plugs, I found there was a significant amount of oil in the #4 spark plug well. After removing the old spark plug, I soaked up the oil in the well and installed a new spark plug. After installing 6 new spark plugs, and driving down the block the engine continued to misfire. Does anyone have any ideas as to why there would be oil in the spark plug well? What are some things I might need to try to get the cylinder to fire normally?

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Originally Posted by 100kVX

My #4 cylinder started to misfire a few days ago, so I decided to replace the spark plugs. When replacing the spark plugs, I found there was a significant amount of oil in the #4 spark plug well. After removing the old spark plug, I soaked up the oil in the well and installed a new spark plug. After installing 6 new spark plugs, and driving down the block the engine continued to misfire. Does anyone have any ideas as to why there would be oil in the spark plug well? What are some things I might need to try to get the cylinder to fire normally?

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A new coil pack for that cylinder?...:_wrench:

Just a thought

Try switching coil packs from one cylinder to another & see if the misfire "moves".

Was the plug loose in the head when you removed it? The "oil" could have come from the combustion chamber but if it was a lot of motor oil, then you a ring may be leaking which is a bigger problem.

When you say #4 cyl, how are you counting them? I've seen the plug wells filled with detail liquid on a buddies which caused it to misfire badly - but the engine sure shined!

What did the plugs look like that you took out? That is probably the biggest help in troubleshooting misfires. Are you using premium fuel?

If you have a 00-01 VX, the computer will often throw codes if using the Bosch+4s (and probably others). What plugs are you using and what did you gap them at?

I have a '99 VX. The plug wasn't loose and was covered with oil when I removed it. I replaced the old plugs with Denso IK16 and I usually use Midgrade/Premium gas.

I'm counting the cylinders as driver's side back to front: 1, 3, 5 and passenger side back to front: 2, 4, 6

I swapped out the #4 and #6 ignition coil as Ldub suggested and think his solution might be correct. The original code read P0304 - Cylinder 4 Misfire Detected. After I swapped the two ignition coils, I got 2 other codes: P0356 - Ignition coil F Primary/Secondary circuit malfunction and P0300 - Random/Multiple Cylinder Misfire Detected. I then cleared the codes and started the engine until the check engine light came on again. I read the codes again and only one showed: P0356.

If I get new ignition coils, should I go with OEM or will an aftermarket part work fine?

I gapped the spark plugs at .04"

Quote:

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Originally Posted by 100kVX

I have a '99 VX. The plug wasn't loose and was covered with oil when I removed it. I replaced the old plugs with Denso IK16 and I usually use Midgrade/Premium gas.

I'm counting the cylinders as driver's side back to front: 1, 3, 5 and passenger side back to front: 2, 4, 6

I swapped out the #4 and #6 ignition coil as Ldub suggested and think his solution might be correct. The original code read P0304 - Cylinder 4 Misfire Detected. After I swapped the two ignition coils, I got 2 other codes: P0356 - Ignition coil F Primary/Secondary circuit malfunction and P0300 - Random/Multiple Cylinder Misfire Detected. I then cleared the codes and started the engine until the check engine light came on again. I read the codes again and only one showed: P0356.

If I get new ignition coils, should I go with OEM or will an aftermarket part work fine?

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Sounds like the misfire moved with the coilpack...lucky guess on my part
I have no negative experience with aftermarket coilpacks, but still prefer OEM...just because I'm weird I guess...:smilewink
I haven't heard of a high performance aftermarket coilpack, or I'd probably have them.:rolleyesg

The odd bank is on the passenger side.
http://www.drivehq.com/file/df.aspx/.../rightside.jpg

The even bank is on the drivers side.
http://www.drivehq.com/file/df.aspx/...x/leftside.jpg

Mark Griffin

Thanks for all the help.

I got the cylinder numbers from a previous post, but Griffin's numbering seems to be correct.

The oil in what I thought was the #4 well was actually the #3 well, but the misfire was in what is truly the #4 well (driver's side middle well). That still leaves me to wonder why there was oil in the #3 well. I'll inspect that one periodically to see if the oil returns.

After inspecting the wires as Griffin suggested, I found that the connection to the #6 coil was loose; causing the new codes. After securing it, codes P0356 and P0300 went away, leaving me with the original P0304 code. I traded the #4 and #2 coils as suggested by Ldub in the above reply and the code moved with the coil. Code P0304 went away and P0302 replaced it. This leads me to believe the ignition coil is bad. I'll try replacing it and will make a new post once I do. The coils are a bit pricey at $138.45 each as quoted by Merlin.

I have not had a valve cover off but would think that there is an o-ring or gasket were the valve cover and the head meet. If the o-ring or gasket is bad you will get oil leaking into that area. shawn

The dip-stick is right below #3 - could there have been a bad seal forcing oil up the tube, to dump in that position? Just a thought.

-- John

It wouldn't hurt to make sure your PCV is still "rattling" to indicate it is probably functioning okay. If it doesn't rattle when you remove it and shake it, that could cause crankcase pressure to build and oil will probably leak from where ever the pressure can escape. I only throw this out because I had a "brand spank'in new PCV" fail on me after I installed it for the trip to Moab :rolleyes:. Started spraying oil out of my breather cap (aftermarket) and I sucked down a 1/2 quart of oil rather quickly before discovering the problem. (Normally she doesn't use hardly any oil in 3,000mile change intervals.)

The downside is that even if crankcase pressure caused a leaking gasket; the damage has been done to the gasket or seal and it will probably need replaced even if you restore the pressure to its proper level (functioning PCV).

The new ignition coil did the trick. No more misfiring. I'll check the spark plug well in a few weeks to see if the oil has returned. I'm also going to check into the PCV. Thanks for all of the tips.