check the tachometer while your cranking in the no start condition, if it is moving I would ignore crankshaft position sensor for sure. I
had similar problem off and on for over a year, twice i replaced ECM and it seem to fix it for 4-9 months. Last thing I did was clean the grounding lug that comes out of the ECM wire harness and was behind a bracket near water pump. so far so good.
Also, every time mine would stall and not re-start, if i just removed and replaced the electrical connector to ECM it would fire right up. did that in traffic more than once.
