Just when i think everything is going ok, my car decides to take a dump on me again.
2 months ago, I went thru this. I did replace the valve cover gasket and spark plug tube grommets. since i just replaced the spark plugs, i skipped those. Well, im still getting OBDII codes 300-305 aka misfire on all cyl. i took a new set of plugs out and swapped them today- and a good thing, too. each one was soaked in oil. as in dripping. the top bit (that you see when you look down into the tube) had a bit of burned oil around the bottom, just above the threads. the threads, and 'gap' area- covered in oil. The tubes themselves dont seem to be protruding any more than usual, they didnt seem loose at all when i replaced the valve cover gasket. I used a bit of anti-seize compound when i did the plugs a couple months ago, and that was ALL OVER THE PLACE!!! to the ridiculous level. i used paper towels and wiped away the oil and compound that i could see, and put new plugs in today. after 15 miles of driving or so, all the error codes were back.

just for reference, this is what i had to do to it last year. i noticed that even then, there was oil on the plugs, but only 2 at that time. now its on all 4 plugs.

Ive done a bit of reading on here and the interwebz, and i am finding 2 likely suspects- the intake gasket and worn piston rings. I might be able to do the intake gasket ok, but pistons.. thats brand new and honestly frightening territory for me. not to mention this is my DD. I can continue to drive it- for now. but something is obviously seriously wrong. Im just not sure what.

Does anyone else have any other suggestions?

 

i should mention that there seems to be no noticeable smoking/oil burning, although a fellow neon owner recently made the comment of 'you car's exhaust smells funny'. this might be because of the evap system maybe- ive gotten code 442 for as long as ive had the vehicle, and there seems to be no drivability problem, nor ready solution.

 

It sounds like the oil is on top of the plugs. Change the valve cover spark plug tube seals. That should be in the valve cover gasket set. When the seals go bad the oil leaks down onto the top of the plugs causing it to misfire. You should NOT have oil on top of the plugs, it would be the same to have the tubes filled with water, the spark travels off the plug before its even in the cylinder. Use champion coppers gaped to spec.

 

yup, i replaced the tube gaskets when i replaced the valve cover gasket 2 weeks ago. i triple-checked the gaps before i put them in, always.

also. there is no other oil leakage, aside from the oil pressure sending unit. there is no coolant leakage nor mix, no overheating.

 

Sorry I though you said there was oil down the threads of the spark plugs, which would indicate the oil dropping when you pull the plug. Oil on the bottom of the spark plug will be caused by a very very weak cylinder. A compression and or leak down test will help confirm weather its the rings, valve, seals. or head gasket.


I still got money on the spark plug seals since you said the car doesnt burn oil.

 

its been a few months, and it hasnt stalled out on me, but the misfire hasnt gone away. now getting P0300, 302, 303, 304. over the past couple weeks, ive put 2 bottles of gasket conditioner into the oil to try to stop up whatever gasket is leaking. the #1 isnt giving misfire codes after the oil treatment, so thats improvement. Debating changing out the spark plugs for giggles and trying to clean it out a bit better, maybe the anti-seize compound mucked things up?? . still havent gotten the tools to do compression test. I do not think the spark plug tube grommets are the cause- i replaced those with the valve cover gasket a few months ago.

im leaning towards the intake gasket. I just now looked up an easy way to check for that, so ill do that after work and see if im right.

based on another post on a different page, i am debating adding seafoam to the oil, running it, then changing the oil. clean the oil and crankcase out real good and start from scratch. new oil, new plugs, oil pan gasket, oil pressure sending unit.

oddly enough, if ive been driving all day, and the engine is good and hot, sometimes, just sometimes, the CEL will go off. o.o i can count the number of times it HASNT been on in the last 6 years on one hand. it went off for about an hour last week i was so shocked i almost hit another car!

 

When you changed the valve cover gasket did you take the plugs out and clean oil off, use a qtip and brake cleaner to clean out the spark plug tube. Gap your champion coppers to spec while your at it. Best way to check for vacuum leaks is a smoke leak tester. What does a compression reading reveal? Is the motor internally up to par? Last time the injectors were serviced? Also I dont have a list handy with the P0 codes. Do the key dance next time and give me the two digit numbers.

 

do a compression test