Engine misfire - P0301, P0304 and P0134

[mikepn]

Hi Everyone,
This is my first post, and I'm actually posting on behalf of a friend.

Anyhow, my friend's Beetle started running rough recently and the check engine light would come on and off. Since it had been a while since the spark plugs were changed, we replaced the plugs and the wires, which made it a bit better, but then it came right back. The check engine light is on, giving the codes in the subject line (cylinder 1 misfire, cylinder 4 misfire and insufficient activity from O2 sensor 1 (before converter)).

The car is idling rough, and it seems to be running a bit rich (at least the exhaust fumes smell rich.) There is visible smoke if you rev it up.

One thing that concerned me - and I'm not sure what might happen if that was the case - it seems that the lube shop might have put in too much oil. When I pull out the dip stick, it appears to be at the highest level in the normal range, which leads me to think it might have been too full. I see warnings all over the engine compartment about overfilling. What actually happens if you put in too much oil?


Does anyone have any suggestions on what might be wrong? Note: the O2 sensor was replaced in 2005 under the recall. Also, the spark plugs are brand new, as are the wires. The mass air flow sensor was replaced in the last few years (not brand new, but not old).


Let me know what you think.
Thanks,
-Michael

[mikepn]

Sorry, I forgot to mention that it's a 1999 2.0L engine.

What's the chance it's the ignition coil?

-Michael

[digitalputty]

I think if there is too much oil ... the catalytic converter can break? I think that is what happens.

I hope thing get fixed up. Sister is having similar issues ...

[05yellowbeetle]

Is it worse after running through a water puddle? Is it worse on days with high humidity? If yes, then change the coil pack. If you already replaced both the plugs and the wires I would change the coil, they are known for cracking. Just before I sold my '98 my brother decided to clean the engine, so it shined. Good idea, except mine had a broken coil, didn't know that for sure until a bit of reading on here after I sold it. Anyway, the car spit, sputtered and in general carried on, it refused to run. My brother had to dry out the coil and the engine in general before it would stay running smoothly.

[mikepn]

Thanks for the suggestion!

If coil pack refers to the ignition coil (link to picture of ignition coil: http://www.autozone.com/images/products/wl2/wl2c1319003.jpg), then we already tried swapping that out. No luck:-(. Are there other parts of the ignition system that tend to fail? Or might this be something other than the ignition system?

Thanks,
-Michael