intermittent problem
 

about every 3-4 weeks my 2000 ml320 when i start it cold, it idles rough and has no power. i turn it off and restart and it runs fine, what is the trouble?

Thanks Ron

Air mass sensor? One of the 4 oxygen sensors?
Just take it to a dealership and for half an hour labour charge they can run a short test and you can replace what is faulty. Much cheaper than throwing parts at it.
If their computer doesn't throw a fault code (but it most likely will) then you may need to leave it with them.
But try a short test first.