I have been troubleshooting this code/issue for a while now. I have rough start up when engine is cold, like the engine is flooded type of symptoms. I have replaced the MAF and troubleshot the pedal assembly. Noticed a hissing sound by valve cover/air box when engine is running and after I shut the engine off. Not sure if that comes into play or is normal.

R56 with 65K miles. I have also already had the tensioner issue resolved after the guide broke for some history.

 

If you have an N14, check to see if you have a hole in the PCV hard plastic line going from valve cover to the intake.

 

I too had the hissing after shut and after replacing the valve cover, all was fine. I did have a code but forgot which code.

With the engine running, move the hoses coming into and out of the valve cover. If the idles jumps or dips, you may have a vacuum leak in one of the hoses. If no idle changes, the valve cover is most likely your culprit. The hissing sound after shutoff is a dead giveaway for a bad valve cover.

 

Your valve cover is bad. Very common .