I have had a relatively steady luke-warm start stumble in my '91 300E. I thought it was the cold start valve leaking down, but my research suggests that these almost never fail. It usually only happens the car is not entirely cold (needle registers something on temp gauge) but not when the car is restarted at or near operating temp (though it does occasionally happen when the car is totally cold). She got a new EHA a couple of years ago, and I have checked duty cycle (back when it was warmer out) and it was w/in spec.
I have read that the resistor in the coolant temp sensor can start to disintegrate sooner or later, creating a problem like this. Think this is the culprit?
I can live w/ the problem, I just hate the sound of the poor girl stumbling and coughing for 15 sec and fear what it might be doing to the engine, running lean like that.
We fixed a similar problem (well, almost entirely fixed) in our '91 300TE w/ duty cycle adj.
Any opinions?
Thanks!
-Matt-

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Currently:
1972 350SL Euro 4spd
1973 BMW R75/5
1981 BMW R80GS
1995 FZJ80 with OM606 Conversion In Progress