Calling all Spark plug specialists

Ok guys quick question here on my spark plugs.

Car: 2.0t fsi Audi A3 143k miles on the clock.
Apr stage 2, CAI, turbo bAck exhaust, stock k03, red coil pack

These are ngk iridiums one heat cooler installed at 108k miles.

Car never had a misfire until last week after I brought the car for a carbon cleaning, now it has misfiring on cold start and for a few minutes, it does not trigger cel, just soft code p031

I replaced the plugs thinking that was the problem, but still getting the misfires.

Can anyone tell me what they think of the conditions of these sparks based on 35k miles (give or take) on a stage 2 map?

This is cylinder 1 - 4 (RIGHT FROM LEFT - sorry only though about it after I took)

Cylinder 3 (middle) compared to 4 (left) and 2 (right)

Close up of 3.

Does this sparks look bad? Cylinder 3 had this oil residue on the thread plus some deposits on the electrode, and all of them had this black soot on the socket (outside of the thread) but I am inclined to believe that’s from the dielectric grease applied to the packs when installed.

Should I be looking into an engine problem here guys? Any advice is appreciated.

Thank you.


The plugs look like they do have some collection on them but they look like they were burning clean. The one plug looks worse and chances are that the valve cover gasket is letting a little oil seep out onto the plugs.

This seems to happen to lots of people. When you get a carbon clean it seems to have the effect of causing misfires. From what seems to be the sorce is cleaned off carbon and other left over compound from the carbon clean makes its way into the cylinders and partially effects the 02s causeing missfires.

Thank you for the input Justin!

The black oil residue around the threat and socket you believe is from the valve cover or just on cylinder 3 (the worse one) because of the deposits on the plug?

I forgot to mention the carbon cleaning was walnut blasting. No chemicals… Does that apply to the same 02s explanation and if so, this would go away after some time or should I replace it?

Thanks again for the feedback man.


Let me refrase my first question:
You believe the deposit on cylinder 3 is from the valve cover because of the oil on the thread, deposits and soot on the socket or just because of the buildup on the spark tip?

Its hard to say exactly what is causing the misfire but from what we have seen lots of guys get misfires after carbon cleans. One of the causes of this is particles getting into and damaging the o2.

If you just had oil in the threads of plug 3 its not likely that the oil is from the cylinder its more likely its leaking from the valve cover seal around the plug itself.

Thank you Justin.
The misfires now are only cylinder 01 (p0301) and another soft code for multiple cylinder misfire (p0300? - can’t remember now) car has not done the rough idle on cold start anymore. I’m going to replace the O2s and the valve gasket and see where it goes from there.

Justin, on a side note, what would be the right blocks to log to see if my engine/k03 are still within healthy standards? Would you happen to know what should I log to get that type of information?

Thank you.