So I've got 208k miles on my W211 with the M112.949 motor. Plugs, and plug wires, fuel pump, filter & sender, engine air filters, high-quality fuel system cleaners (ie Techron, & another great one, i forget name) have either been changed or used in the relatively near past.

So here we go: upon quick throttle, usually from a stop, the engine totally cuts out/bogs for a moment or two (doesn't seem like a misfire), and if I keep the gas on, probably to the floor, the engine suddenly & seemlessly revs up properly like the powerhouse studly motor that it is.

So, the problem is often intermittent, and has occasionally stalled while at a stop or idle or switching between fwd & reverse gears.

WHAT COULD THE PROBLEM BE!?

I'd like to know if it could be the throttle body, or maybe MAF or other sensor or WHAT could be causing this? It is progressively getting worse. It seems to me as if it were the throttle "motor" sticking in the housing... but I could be way off base.

I have no MIL (check engine) light on FWIW.

What gives???

__________________
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!)