I'm trying to diagnose a P0301 code - cylinder 1 misfire. The car had new spark plugs installed by the dealer when I bought them - turns out they're some kind of Bosch Iridium plug I couldn't look up on google. I noticed that the spark plugs have some oil wetness around the washers. The coil packs didn't have any obvious fouling. Here's the album: http://imgur.com/a/DDpRy


I changed the plugs to NGK 7772s, and swapped coil pack 1 to cylinder 4. I cleared the codes and have a P1399 pending after a little driving, but no specific misfire yet. I also did a compression test and got good results, if a little high. - #1 248, #2 241, #3 235, and #4 247

 

Looks like quite a bit of oil on those threads. Not sure about the misfire. If compression is good and the plugs are gapped properly I don't know what else would cause it other than a bad injector/coil pack

 

The blackness on the threads was dry (burnt oil?), the only wet part was the washers.

 

Perhaps. You should check your spark plug tube seals just to be sure. It doesn't look like the coil packs have any oil on them though. Were all the spark plugs torqued correctly?

 

No idea if they were initially, but when I replaced them with NGKs I torqued to 20 ftlbs. I just ordered four new spark plug tube seals, 12342-pcx-004. Going to pull the valve cover for the first time next weekend to check valve adjustment (it was done by a mechanic in January but I want to make sure) and install the new seals.