M103 W126 Misfire/Sputtering only at certain times

[redassag00]

Hi All,

Wondering if I can get your expert M103 advice. I've been working on 617 and 603s for a long time, so I'm kind of green on the gassers.

Working on my 91 300SE. 270K miles.

Heres what I'm experiencing:

The car starts and idles fairly smooth, if you accelerate gently, there are no problems. However, if you give it more like 1/4 to 1/2 throttle, the car sputters and coughs, and stops accelerating, then eventually will work itself out and go back to normal. This is especially fun when pulling into traffic.

In the driveway, idling in park, if you rev it gently, you can work up the rpm just fine with no drama. If you give it 1/4 to 1/2 throttle to rev it up, the engine does the whole "chug, cough, sputter" like its about to die, then comes back alive again and acts normal again.

Car has new:
Fuel Filter
Plugs (non resistor)
Cap
Rotor
Plugs
Wires
Engine Mounts
Oxygen Sensor

Any advice?

Thanks in advance!