2007 S550 88K miles. On occasion at idle in gear will act like there is a misfire. Can happen when slowing at a stop light or when in reverse and shifting into drive. Only at an idle. Put in neutral and idle is smooth. Off idle everything is OK. Mileage is OK. No check engine light. Have changed plugs, checked for vacumn leaks. Very intermittent. Code 5001 shows up.

 

Code 5001. In what module does it show up under and what is the description for the code?