Hi all. My 2005 E320 CDI would crank but not start when hot. Sometimes it would go for a good 10 seconds but never catch, other times it would crank for just a couple seconds, and sort of "stall" out. It threw the code P0336 (Crankshaft Position Sensor) so I replaced the sensor with a Bosch part. The code did not come back but a few days later the problem returned. I replaced the sensor again thinking I may have gotten a bad part. Things were fine for about 3 weeks but the problem is back yet again. No codes this time. Cold starts are no problem, nearly every time the engine is warm it takes multiple attempts to get it to start -- in many cases nearly running out the battery. On occasion when this happens, I get the "Coolant - Visit Workshop" message on the dash, but again there's no code, and no CEL. Any ideas?

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05 E320 CDI - 185K miles
82 300D - 200K miles (sold)