mikemessi

Any updates?

kepro74

please keep us posted here! i have the same now; misfire , always on #2, i changed spark plugs, coils, injector nozzle, tappets on no.2, changed variocam and valve lifter, checked valve springs, leak tested, compression checked...

All is GOOD, fault persists.

Need ideas pls! :-:

droptopguy

No idea what is going on there. It sounds like you changed all the parts you were supposed to change. We did eventually get rid of the car above. It was just too much "up in the air" BS. Running fine at one point after some fuel treatments but traded it in anyway. As far as I know the problem later resurfaced and it had to have the entire offending bank's cam followers/lifters replaced. Was recently considering a 2013 991 Carrera but knowing it has the same engine I just don't know if I'm willing to chance it.

albi123

Going through the same thing , did coils , plugs, solenoid and an INJECTOR all to get to the real problem which was a burnt exhaust valve. Expensive lesson because I bought it without an over rev report because the dealer said it was all part of their 100 point inspection. Had a couple #4 revs by the previous owner

spaceflowers

I had similar issues, and found that I was overfilling the gas tank. I was topping off. When I stopped doing that, the problem disappeared. I stop fueling when the automatic sensor stops the pump. Stalling/stuttering issue absolutely gone since I used this method.
-2011 Carrera with 95K miles.

Hula

Resurrecting this old post. After coming off the highway got a rough idle with associated check engine light. Pulled the same codes except the misfire and valve solenoid fault were for cylinder #1. Cleared the codes. Got a smooth startup but experienced the same symptoms and same codes after a highway jaunt. Indy shop recommended replacement of Camshaft and Valve Lifters on that bank. $3,200. 90k miles on a 2011 4S

Hula

Correcting the previous post to add to the knowledge base. I didn't need a new camshaft but the camshaft does need to be removed to replace the lifters. Also didn't need to replace all the lifters on the bank. Just the lifters on the misfiring cylinder. My mechanic blamed a pin in the internals of the lifter itself. He's seen this a couple of times before. Replacing the lifters solves the problem but labor is intensive. It's proper surgery.

Hula

Well my third post on this issue. Same original error popped up soon after the lifter replacement. My mechanic hooked up some diagnostics and let it idle for a few hours. He discovered an occasional short duration oil pressure drop off. The faulty part turned out to not be the sensor. Not the lifter. It was the oil pump regulating valve. Sounds scary. It's been three months and a few thousand miles since the valve replacement and I'm declaring victory.

Prairiedawg

Very interesting. This is with a 9A1 engine?

Keep this thread updated please.

SpectreH

I’m glad the issue was solved. Thanks for the follow up as well.

docdrs

hula, thanks for the updates ….good to know you found the culprit

996AE

Strange this would only throw a misfire code on a single cyl?

Hula

Yep. Symptoms started at idle, soon after a start, with a "Oil pressure monitoring defective" warning on the dash with the indicated oil pressure dropping to zero. No change in engine idle. Lasted about 10 seconds before the warning self extinguished and the oil pressure needle jumped to a normal reading. It happened again a few weeks later so I figured a sensor going bad. Not a lot of data on this failure mode and difficult to reproduce but my mechanic agreed and replaced the oil pressure sensor. About 200 miles after the repair, coming off the highway and sitting at a light, I got the misfire and fault code. A restart solved the misfire but back to the shop. Code and misfire indicated bad lifter. After the new lifter, coming off the highway and sitting at idle again, the "Oil pressure monitoring defective" warning returned.

My mechanic is a long time Porsche tech and he reached out to others in the community. I don't like the parts cannon approach but he found the right info and performed right test to isolate it to the valve. $1,600. About half of that labor. I wasted a lot of time and money chasing this one down. I considered a Toyota at my lowest point but it's back to running strong now.