So using my (very basic) scanner, I keep getting these codes via OBDII:

PO104 - B2/5 Hot film mass air flow sensor: Check wiring of signal line & voltage.

PO221 Fault of function monitor in electronic accelerator.

PO300 - Misfiring, Damages TWC
PO305 - Misfiring of cylinder # 5 (see currently valid STIP?)
PO306 - Misfiring of cyliner # 6 damages TWC (see currently valid STIP?)
and...
P0445 - Purge control valve (short circuit to UB or Ground / switchover valve currently open or closed).

So I presume I need a new MAS? clean or replace?

Also, I suppose this explains my accelerator hesitation sometimes w/ the electronic accelerator... what to do about this?

And I'm having a bad misfire that comes on after car is amply warmed up... sometimes it shuts down one cylinder, and sometimes 2 are shut down and then she's running REALLY rough. Will only be better after I let the car cool down and then restart. If I immediately restart - misfire coming RIGHT back.
I have replaced plugs & wires recently, used a couple of high quality fuel injection cleaners (Lucas, Techron), recently had a new fuel pump, filter & sending level unit. The only other things I can think of would be a bad fuel injector(s) or ignition coil?

And what is the Purge control valve? I'm going to look it up right now!

Car is a W211.065 with the M112.949 motor at 211,000 miles!

Please help! Thanks!

__________________
2006 E350 w/ 155k miles (Daily Driver)

Previous:
1993 300E 3.2L Sedan w/ close to about 300k miles
2003 E500 Brilliant Silver (Had 217k miles when totalled!)
1989 300E with 289,000 miles (had for <1 yr while in HI)
03 CLK 500 cabrio (Mom's)
2006 C230k (Dad's)
1999 S420 (Mom's/Dad's)
2000 C230k Sport sedans
2001 CLK320 Cabrio (Mom's)
1995 C280 My First Mercedes-Benz... (155k miles. EXCEPTIONAL AUTOMOBILE. Was Very hard to let go of!)