All of this sounds so familiar. I had all of this with my 84 500sec. I spent a lot of money on ignition parts, wires, dist cap, etc. Also spent money on some fuel system diagnosis, etc.

Finally one day I was complaining to a former mercedes dealer mechanic and he said "always depress the throttle part way on start up". I did that and since it starts a lot better. I also changed my habits by not turning it off for a stop at the vp for a few minutes.

It never got worse.

I also would put some injection cleaner through it every few months.

Tom W

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.