30K Mile Service Question

[rogerjohnsen]

My car recently went through the 30K mile service and I had a few questions I was hoping to get answered. First some history: I have been getting CEL's with codes P0300 and P0306 when the car is at idle shortly after starting the car. I pulled the plug on the No. 6 cylinder and found it was gapped at .4mm so re-gapped it to .8mm. Since then I haven't experienced any further CEL's in the last half-dozen times I've started it. The car now has 33K and is an '04 911TT cab.

I've attached pictures of the No. 6 plug:

The plugs are BERU, however, I've been told Porsche has replaced these with BOSCH. Are BERU plugs still acceptable for Porsche dealerships to use?

Is it normal for a plug to look like this after 2,170 miles?

Should I be concerned about the oil on the plug threads?

Should I be concerned about the recorded misfires with respect to engine damage or anything else?

The Porsche Dealership service record shows the part number for the plugs used as 999-170-195-90.

[rogerjohnsen]

Nobody?

[Loren]

The plugs are BERU, however, I've been told Porsche has replaced these with BOSCH. Are BERU plugs still acceptable for Porsche dealerships to use?

Porsche uses Borsch and Beru interchangeably. Some folks swear by one or the other - but I have never seen any difference in life or performance.

Is it normal for a plug to look like this after 2,170 miles?

They look normal to me.

Should I be concerned about the oil on the plug threads?

Not unless it is on the tips.

Should I be concerned about the recorded misfires with respect to engine damage or anything else?

Misfires are always a concern as they can cause cat damage and if bad enough valve or ring damage.

Check the coil packs for cracks and also check the electrical connectors for corrosion or damage -- and of course, make sure someone did not forget to torque the spark plug down. (it is not uncommon to forget one and then get misfires because it is loose and leaking compression).

[rogerjohnsen]

Thanks Loren - this makes me feel better. Hopefully the misfires didn't cause any harm - not sure how to check that part though. The coil pack looked okay - no cracks or corrosion. The plug also seemed to be "snug" but I torqued it to spec on re-install after re-gapping the plug. Whatever was causing the misfire seems to have vanished now as I still have not seen a recurrence of the CEL and no pending codes noted.

[ADR3NALINE FIX]

Your plugs look amazing after 30k miles. Mine are more burnt that your after 300miles.

[rogerjohnsen]

Your plugs look amazing after 30k miles. Mine are more burnt that your after 300miles.

Cool - the plug actually has just over 2k miles in that picture.