Rough idle, CEL, related?
 

My 2011 Cayenne S was brought in for the camshaft bolt issue, which Porsche covered.

I've noticed the vehicle can have a very slight rough idle at times, especially when cold. Figured that was normal.

Recently a CEL came on. Evap system very small leak. Replaced fuel cap and reset CEL, but it came back.

Then, this morning on a very cold start, I was idling at a stop light and it started idling very rough, the CEL was blinking, and PSM failure and start stop deactivated warnings came on. I immediately stopped and turned it off. When I turned it back on, it was fine.

Any insights on what might be going on here? Trying to decide between taking it to the dealer that did the camshaft work if this could at all be related, or if emissions warranty could pay for whatever is causing the very small leak. Other option is one of my Porsche indies.

Ran codes, nothing new. Still P0456

hi about plugs?
My 12 CTT had only 40 k on them, and at times idled a bit rough (now Turbo do have tighter plug intervals). When I did New plugs, I couldn't believe how much better it ran, absolutely silky smooth on idle, and more responsive...126k Mi too!
All those lights could be triggered by just a random plug misfire, I suspect...It's all tied together ya no. As Chevy Chase would say,,,'it's all ball bearings now days'
Hoping plugs would be all my friend. Otherwise, fear the reaper

Did you get this fixed? I have the exact same behaviorist. What was it?

It's not related but when I had a 'small evap leak' on my '06 Jeep it was a hose fitting on the circuit running from the tank to the filler neck. Did the fuel cap bug hunt, but only managed to nail down the problem by dropping the tank and replacing that hose.

My point is not that it's the same hose but that 'small leak' could be damned near anything related to how the system manages fuel tank pressure.

One thought comes to mind, how empty have you been letting the tank get? And how do you park it, flat or on a grade?

I had a failed evap leak detection pump.

no issues since, but might replace spark plugs to be safe. Previous owner did coil packs less than 10k miles ago so hopefully those are ok

i replaced the Gas Cap about a week ago, so far so good, no CEL