I agree with Steve about intermittents being a PITA and car owners not understanding why you can't find the problem. I had a 90 300SEL drive me crazy with intermittent stalling and not starting. It never stalled for me. I was down to swapping parts. Iwould put a part in and the car ran fine for a couple of weeks, and then I'd get the call that the car was dead again. I finally hit it with an EZL module. I had a 500SEC with intermittent run and stumbling. A new coil took care of that problem. I had a 560SL die and restart. I could let it set and idle for hours. I got lucky on that one. I was monitoring fuel pressure and saw primary pressure drop off. Fuel pumps solved that one. I would look at those components. I've never replaced a crank position sensor. I'm sure parts houses sell alot of them to be installed on cars that have been mis diagnosed.

Good luck,
Peter

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