rough idle sometimes
 

Hi all great site, and thanks in advance for any advice.
I have a 2005 c160 that had a maf error showing and rough idle, changed the maf which cleared the code but then popped up a oxygen sensor code. I took it to a merc specialist not a dealers, who diagnosed the crank breather pipe and valve problem. So had those done. The car is running alot better but very randomly still idles rough and the oxygen sensor code is still showing. Its wierd as in nuetral or park its fine just in reverse or drive it judders, sometimes really bad other times very slightly, or runs smooth like nothing wrong. Also theres a slight delay in power when i put my foot down, not sure if this is related
Any ideas thanks
Chris

Clean the throttle body

As dumb as it sounds, check the alternator pulley. It should freewheel in one direction. If it's seized, it needs to be replaced. My car used to idle funny in gear (D or R) until this was fixed.

With that said, looks like you still have that oxygen sensor to deal with.