Hello,
2006 Hemi Durango. 197,000 miles. New Jasper engine at 100,000 miles. I do all my own maintenance unless I don't have time. In Nov last year it cranked fine but took about 10 seconds to start and ran rough. Crank sensor code and oil pressure sensor code came up. Changed the crank sensor and still wouldn't run right. Changed the oil pressure sensor and it ran great for about a month. It started to need more cranks to start and eventually wouldn't start at all. No code. I changed the crank sensor and it was fine for about 2 months. Again repeated cranking and would run fine once it started. No code. Changed the crank sensor again and it was fine until last week. Extended crank and then started. No codes. Had a shop check it out they said nothing obvious but suggested I change the fuel pump assembly due to mileage. I did that and no issues until today. Cranked over nice and started quickly like it should. A few minutes later it died and was a bear to get started but it eventually ran and ran rough for a few seconds and threw a crank sensor code and then a misfire code. Always when it cranks the tach registers RPM.
I changed the crank sensor and boom it started right up. I checked the wires I could see without tearing the harness apart and didn't see anything obvious.
I used a few sensors from one local store then switched the last time to a different store but found out different brand sensors made by same company.
I plan to take it to the shop tomorrow with 2 of the old sensors. Can they test those? Can they unplug the sensor and do any tests on the wires?
Am I just getting bad sensors?
Thanks.

 

Have you check the wires from the oil pressure switch and to the sensor. I have seen the wires chaff on the engine block. Also are you using Mopar sensors.