Well, my problem came back in late fall, too far into the winter season to address, here's a summary now:

Cold Start: 1-2 sec crank, 3-4 sec stumble/mis, then OK at 900rpm

Drive-650 rpm

Scenarios:

1. Temp at 80 +, 20-30 mins of driving. Let sit 10-15 mins (hot soak),
starts up, 1 sec of stumble mis, 10-20 sec hesitation/mis, then OK.

2. Temp at 80 +, 45 mins driving. Let sit 45 mins. 3 sec of stumble mis, 1-2 minutes of hesitation/mis, then OK for 7-8 mins, then hesitation is
back but 8-10 mins later its gone.

This is driving me crazy. I've spent alot of time here researching the posts and I'v come up with a list of suspects:

1. OVP: I've checked mine and fuse was good but it was not mounted-
it was dangling free....any chance of damage...?

2. Crank Position Sensor

3. Fuel accumulator

5. Engine temp sensor

I could really use some expert advise. Update on what's been replaced
from previous post:

My indy replaced 8 plugs, both caps & rotors, wires, both coils,
all 8 injectors and three days trying to isolate/correct the problem but no luck-
he is referring me to Mercedes. We're both frustrated and disappointed.

Mechanic is excellent and a great guy, no charge for time and parts-
all returned back to stock.


My last entry on this post:

Sorry for the delay in responding but lots has been going on.

To recap, my local indy couldn't locate the problem, 2 weeks in the
shop, chasing ignition/fuel delivery, replacing numerous parts, leaving
some on, taking some back, no charge by the way, but he gave up.

Instead of taking it to the dreaded dealer, I took it to a different
indy that specializes in Mercedes.

Summary:
Condition on way to different indy: Cold star rumble, 2-3 secs, after warm up, car would occasionaly mis fire, in drive, at idle , waiting for red light, hesitate on accelleration, but eventually (15 mins later) run fine. Noticed oil guage drop below one bar, and idle would "hunt" in park/nuetral.

New indy had the car for a week and ran numerous tests and concluded that
the fuel distributor was lthe likely cause. Once replaced the car idled fine, no mis fire, and no hesitation. I tested the car for about 30 mins, got it hot, and all seemed fined although I had feeling the car wasn't as "quick" as it was before. After paying the bill and the car sitting for 10-15 mins, I started to drive off and the hesitaion was back. Indy drove and confirmed
hesitation. Indy replaced fuel accumultor with used spare, problem was worse. Replaced with the original and problen was the same: worse. Indy kept the car for a couple of more days. In the end, I was told: "fuel distributor and fuel filter was replaced and air/gas ratio was set to address idle and hesitation problem. Tomorrow will be two weeks and so far so good but I haven't had some real long drives but I haven't experienced the problem like I normally would have based on my "normal" driving habits.


Current status: initial "rumble" at cold start for 2-3 secs. then stable idle, idle also stable after warm up, no hesitation, oil guage still drops beow 1 when hot, performance is strong.