My 300E has been transformed with 1/4 turn clockwise on the EHA adjustment screw.

Prior to Adjustment:
Very weak startup when cold, engine would stall unless I gave it gas. Having A/C on made it even worse, so A/C always had to be switched off when starting. Had to hold gas pedal for about 1 minute before putting car in gear, or it would stall. Once in gear, had to give it gas and get the car moving right away, otherwise it would stall. Not the greatest impression in a parking lot full of coworkers or friends. Once moving, I could finally turn on the A/C without fear of stalling. After driving for about 5 minutes, everything would level out. The car wouldn't stall, but it would come close at times. At stop lights the idle was very rough and erratic. The engine would stumble from a standstill and would hesitate and sputter when gas was applied while moving. The car used to idle perfectly but slowly degraded to this condition over the last 2 years and 30K miles.

After Adjustment:
When cold, engine will stall if I put car in gear immediately after starting. I either have to wait about 30 seconds or rev the engine a couple of times before putting in gear. But after that, everything is fine. No rough idle, no stalling, no stumble from standstill, no hesitation or sputtering. It's almost back to where it was a year ago.

I will test the coolant temp sensor, but I no longer suspect it. I tend to suspect the fuel pressure accumulator. Attempting to remedy these issues, I cleaned the ICV, looked for vacuum leaks, changed the sparkplugs, inspected the wires (which only had about 30K on them), and even replaced my cap and rotor. The cap/rotor also had only 30K on them and when inspected had only slight wear. I should have gone with my gut feeling, as replacing the cap/rotor didn't improve anything one bit.

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08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280

It's amazing what a quarter turn can do. I've experienced the difference in both start-up and in acceleration from standstill. The thing that baffles me is I started down this path in experiencing sudden lack of power during starting from a light or when pressing the gas hard on a turn or braking hard on a turn (stalls). While I haven't experienced the same level of issues since the 1/4 turn exercise, I still need to artfully apply the throttle to get power as needed - can't just press the pedal down hard. Is this normal? Needless to say the symptoms are intermittent. I've cleaned out the choke plate, have clean air filter in place and adjusted the aforementioned 1/4 turn. Anyone have other ideas of what may be going on? Of particular concern is the tendency to stall during hard braking on a turn. Just for reference, the car has 207K miles and had the engine rebuilt around 150K.