CEL on .2GT3 - Cylinder Misfire Detected P0300
 

Anyone experience Cylinder Misfire CEL on their .2GT3. Search has not found anything useful for the 991 GT3 except an oil overfill which shouldn't be the case here since I had the first free oil change done in Jan and the cars been running strong for the past month +200 miles.

Trouble Code(s)
P0300: Random/Multiple Cylinder Misfire Detected
P0304: Cylinder 4 - Misfire Detected
P0303: Cylinder 3 - Misfire Detected
P0305: Cylinder 5 - Misfire Detected
P0027: Exhaust Valve Control Solenoid Circuit - Range/Performance (Bank 1)
P0029: Exhaust Valve Control Solenoid Circuit - Range/Performance (Bank 2)
P0029: Exhaust Valve Control Solenoid Circuit - Range/Performance (Bank 2)
P0029: Exhaust Valve Control Solenoid Circuit - Range/Performance (Bank 2)

Are you running high flow cats?

I had 2 cylinders misfire on my 15 GT3 and they both were due to spark plugs. I had 1 cylinder misfire on my GT4 and it was due to a bad coil pack.

Spark plug or coil pack is a logical thought, but unlikely since it happened on 3 different cylinders. Seems like some sort of electrical system malfunction (bad battery connection or ECU fault?).

Have you disconnected the exhaust valve solenoid electrically because it's setting a circuit code? Also,have you unplugged the vacuum supply hose without plugging it with something? If yes,you will cause a vacuum leak that can cause misfires on both banks...

That makes sense...

The car is completely bone stock.

No mods to exhaust value, the only mod has been a corner balance.

Sounds like a vacuum line could have fallen off the actuator or you may have a bad part there...

Alan, did the 2 cylinder misfire happened at the same time or 2 separate occasions?

hmm, i wonder if this is related to the battery running low a month ago (mid-Feb) due when i wasn't able to drive it for about 3-4 weeks due to weather.

Could be - does the car run smoothly now? Does Sport exhaust button seem to operate properly at idle?

Good idea to get a battery maintainer if you're not going to drive for more than 2 weeks...

Again : P0027: Exhaust Valve Control Solenoid Circuit - Range/Performance (Bank 1)
P0029: Exhaust Valve Control Solenoid Circuit - Range/Performance (Bank 2)

These are CIRCUIT codes! That means those solenoids are either UNPLUGGED,a WIRE is broken(highly unlikely since it's on both banks),the DME(engine management computer is bad)-again unlikely,or the actual solenoids are bad-unlikely again for both to be bad at the same time. The only thing I have in mind is that someone was in there for some reason...

Also,BEAR IN MIND...if you've used a regular code reader the generic " P " codes might not give an accurate description to this car...in other words P0027 and P0029 might not mean what you've posted...pure speculation at this point.

The misfire codes are 100% accurate,no matter what reader you've used...

Start with the solenoids...something is fishy there...

We have had cars that are heavily tracked need new spark plugs. The plugs themselves break inside of the mounts and literally spin around inside.

Its running smooth all this time even with the CEL, but I haven't driven beyond 3k rpm while its having a CEL. The PSE works, there is a change in the exhaust note at idle. However, the sports button is disabled.

Unfortunately I can't get a battery maintainer since i'm in a condo garage without access to AC power :(

Thanks, I'll get on some lifts this week to see, but I think you may be right the P0027 codes may not be accurate as the PSE button at idle does change the exhaust note.

Not heavily tracked, only 2 track days, around 300 miles in 2018. car has about 4000mi in total so far.

probably lack of sunlight here in the pnw and just goes to prove these cars also melt in the rain ;)