I was told by two Mercedes Service shops that I need to check for vacuum leaks first, before I replace my MAF. How does anyone check for vaccum leaks? I am getting a code P0170

 

I would suggest by process of elimination that you disconnect one hose at a time and if that hose does not make a difference in the way the car runs, chances are it needs to be replaced. The good news is that rubber tubing is not expensive so this is more of a "labor" of love than anything else. I would go to a local hardware store and pickup a few different sizes and lengths and have at it.

If you don't have the patience the MAF can be had for about 50.00 on eBay. A steal as far as I am concerned.

http://motors.shop.ebay.com/i.html?_...506.m270.l1313

Good luck!