Hello.. new member with a 99 A4Q, 2.8V6 and 5spd manual and about 93k miles.

I have never worked on my Audi but I do a bunch of work on my jeeps CJ so I understand a bit about cars... just OLD cars..

My CEL came on and codes indicate an 02 sensor issue (bank 1, row 2 or something like that) at the same time it's telling me cylinder 4 +5 are misfiring.

I pulled all six plugs to inspect. Cylinder 4 and 5 plugs look different than the rest... white ashy covering on the electrode, which I assume to be from it running either too hot or too lean. Am I on track or is there something else that could be causing it? I plan to replace plugs first and attempt to reset the CEL, but based on that condition, can anyone tell me if I should go ahead and replace the wires and coil pack anyway?

Second issue, more troubling to me: as I pulled the plugs, the #1,2, and 6 plugs came out with oil on them... I noticed that the oil seemd to be sitting down in the spark plug well (it didn't appear to be burned on the plug on the inside, but fresh oil on the spark plug socket and the threads of the plug). Most significant amount was on #6. I had noticed two weeks ago when I started the car there was a bunch of blue smoke from the exhaust at start up. It did it one more time that week, but then never again. Head gasket? Something else?

I appreciate any background or personal experience that any of you all can share with me. Thanks

 

and second question: which of the onlineparts stores do you all recommend? there seem to be a few that specialize in replacement parts, just looking for a referral, thanks

 

Change all 6 spark plugs, and before you change the coilpacks, test them to see if there's a spark. If there is, they're still good for now so dont waste 100-150 per coilpack.

Change your fuel pressure regulator for the misfiring of cylinders. Your current fuel pressure regulator maybe be drowning your cylinders. And definitely change your O2 sensor. I think Bank1 Row2 is before tha Cat, I THINK? lol

You can get all these parts from Pepboys, Autozone, etc. You might need to order some of them. Let me know if this helps.

 

Bank 1/ 2 is post catalytic converter, so this wouldn't be the issue.

 

do a compression test ( oil or black on the plugs is normal for a poor stater ) please post the fault codes not the symptoms since you know them

 

You might need a new valve cover gasket set if you've got oil on the plugs.

 

thanks for the responses

fault codes were: P140, P300/304/305

it appears the oil was only on the outside of the plugs.. but that wouldn't make sense for my blue smoke two weeks ago (which has disappeared)

 

I think you need to replace your catalytic converter...you might just need to visit your dealer...