Another update- yes these are real tears dripping on the keyboard...after my last post the 300e was on its way 'home' after having the oxygen sensor replaced. Another driver experienced the same highway speed hesitation- the car seems to turn off and then back on- and when he got off the road slowed down- STALL. So back to the shop for a crank sensor replacement. Vehicle ran like a dream- for 3 days.

Now in addition to the pause- almost like your heart stops beating for a moment then starts back up again- at 55 mph, at low speeds under 10mph tach and fuel pump needles fluctuate- when the tach drops quickly and does not recatch it stalls- but the new symptom- car accelerates on its own- foot off the gas in traffic and again when on gas around 40mph just keeps on going-if I experiment to see what happens it continues to accelerate to about 55 then lugs and it feels like there is a parachute or something open holding the car back.

I have mentioned to service OVP, fuel relay wiring that have been posted answers but we've replaced cylinder head (back when oil in the coolant, wondering if this did some irreperable damage) MAS, O2 sensor and crank sensor. I am definitely afraid to drive this car- so what do you think- give up?