I have cleared the codes, and they do return.
I have heard a clicking sound in the engine bay. So this returns fuel to the line when running too rich.... I have had a faint gas smell sometimes, and also, would this be why when refueling, the DAMN pump ALWAYS clicks off?

Also, no, how involved is checking/clearing all of those vacuum lines? What would an expected cost be if had this one at a reputable mechanic?

ANy clues as to the misfiring?

Thanks SO MUCH you guys!

__________________
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!)