FEOA Forums banner
1 - 6 of 6 Posts

·
Registered
Joined
·
2 Posts
Discussion Starter · #1 ·
Noob in need of help. I am a 2 1/2 - 3 wrench mechanic out of 5 wrenches and have come across a vexing problem. My engine has 198,000 miles and cylinder 4 is misfiring so I went to swap plugs and ignition wires for general tune up/ troubleshooting to find the spark plugs literally swimming in oil. Plugs were wet above and below so what I did was clean and replace Valve Cover Gasket, Spark plugs and put in a new PCV valve. Cleared the code for misfire and ran for a day before code kicked back on and pulled the plugs again. Valve cover job fixed oil accumulating above the plugs and now the only plug wet with oil on the bottom is still cylinder 4. I need advice on where to go from here and what I can do as far as to diagnose what component/ components are failing, how to fix/ any work arounds for the meantime. Im open to engine rebuild/ engine swap with remanufactured engines being something to do but really want to get at least 1 year of driving with this engine before I need to dive into an expensive and major repair. Thank you all.
 

·
Registered
Joined
·
2 Posts
Discussion Starter · #3 ·
Those little rubber grommet looking things that goes on the bolts to the valve cover? IF thats what you are talking about then yes, if not then no.
 

·
Super Moderator
Joined
·
10,375 Posts
i am presuming this is a DOHC engine. The space inside the valve cover is always s hurricane of oil mist when the engine is running. The grommets on the bottom of the tubes that the spark plugs go down into keep that oil from collecting around the spark plugs. Usually this oil is harmless around the plugs, since the oil isnt much of a conductor to cause misfiring of the spark plugs. If there is oil around the plugs, when you remove a spark plug, the oil will run down into the cylinder, getting the bottom of the plug wet in the process. A new dry plug shouldnt have oil on its bottom, at least not right away,
So its possible you have another problem, in addition to the leaky spark plug tubes. i would do a compression check and let us know what the readings are. A bad misfire can result in the plug tip getting dark and wet - from unburned oil from the cylinder walls - which misfiring could be caused by a bad spark plug wire, or a bad distributor cap (such as from a crack in it). I had a random misfire that would show up at high throttle openings. This turned out to be a bad wire inside the spark plug wire where it fit onto the top of the plug.
 

·
Registered
Joined
·
14 Posts
Haha literally having this same issue. No problem before tune up, replaced serp. belt, valve cover gasket, air filter, oil change etc. and suddenly I have a 304 code + 171, engine running like shit and can definitely feel the misfire. Replaced the spark plugs last night, still no luck. Think an intake hose got damaged or something. Replacing ign. coil tonight but will be monitoring this thread in case you get it figured out.
 

·
Registered
Joined
·
34 Posts
Vacuum/Air leaks?
The most common poor running issue I’ve seen on these engines are the two rubber vacuum elbows decomposing. One is on the front driver side for the PCV valve. The other is on the back underside of the intake manifold. Since these literally melt it is hard to see any splits without touching them (melt right in your hand).
 
1 - 6 of 6 Posts
Top