At wide open throttle (button under acc. pedal depressed), the O2 sensor is indeed offline. When my O2 sensor was going bad, but prior to illuminating the "check engine" light, at 1/2 to 3/4 throttle the car would surge a bit, just noticeably.

Frankly, your symptoms sound like bad distributor caps-the M119 in your car eats the distr. caps & rotors every 50-60k. I doubt the O2 sensor would make it feel like a miss.

Good luck!

__________________
"If God had meant for us to walk, why did he give us feet that fit car pedals?" Sir Sterling Moss

Michael
2014 E63S Estate
2006 SLK55
1995 E500
1986 Porsche 944 turbo