Hello, all. Brand new to the forum. Just got an 07 R56, N12 with 97k on the clock. Driving it home I noticed, after a few miles of driving, that it was idling very rough when almost stopped and stopped. There was also a bit of lag when getting on the gas from a stop and a slight loping when cruising. I get her hooked up to my diagnostic tool and pull a P2414 and P0302.
I changed out the upstream o2 sensor and, starting it up, the engine would rev up to 2500 for a few seconds, then bounce between 1500-2500. Put it in gear, then back in park and it was idling rock solid. Took it for a test drive and the rough idle came back when I got back home (P0302 again), with the exhaust smelling rich.
Pulled the plug and noticed some carbon fouling on the base of the insulator and on top of the piston. I changed out the coil pack and it did the same warmup as before. I noticed less stumbling on acceleration and slightly less loping at constant speed. Get back home and wham, rough idle and P0302 again but with proper smelling exhaust. I'm at a bit of a loss here and would like to get her on the road soon.
I changed out the upstream o2 sensor and, starting it up, the engine would rev up to 2500 for a few seconds, then bounce between 1500-2500. Put it in gear, then back in park and it was idling rock solid. Took it for a test drive and the rough idle came back when I got back home (P0302 again), with the exhaust smelling rich.
Pulled the plug and noticed some carbon fouling on the base of the insulator and on top of the piston. I changed out the coil pack and it did the same warmup as before. I noticed less stumbling on acceleration and slightly less loping at constant speed. Get back home and wham, rough idle and P0302 again but with proper smelling exhaust. I'm at a bit of a loss here and would like to get her on the road soon.