Thanks for the info inspector1.

I searched the forum, and most of the P0170 code seems to trace to the air mass flow sensor. So, if P0170 is not air mass sensor, what is it?

See this link:

http://www.whnet.com/4x4/mb-dtc.txt

Other MB tech (stevebfl) stated in other post that this may be caused by a loose purge valve.

Thanks for the replies.