I'm resurrecting my 2006 non-turbo intermittent good crank but no start issue in hopes of any new ideas...
In 2018, sometimes it ran poorly, threw a code, limp mode, & a new cam position sensor solved it.
Also in 2018, the fuel pump failed. I confirmed it fired on starting fluid. I replaced fuel pump, it ran fine again.
Then for a bit in 2018 the car would usually start instantly 9 of 10 times, but
1 in 10 it would crank great but seemed to lack spark, no hint of combustion.
On the 2nd crank attempt, it would usually start perfectly, purr fine, no problem.
I think (guess) that was the beginning of a flaky, intermittent connection somewhere.
I installed new plug & wires, no help.
Problem gradually got worse till one day wouldn't fire at all, cranked great. Starting fluid had no effect.
I decided to throw 3 NEW parts at it: crank sensor, cam position sensor (again), coil pack.
It seemed to solve the problem, instant starting, great running.. I really thought it solved.
For maybe 5 weeks my grand-daughter used it daily around town, to school, the YMCA, no problem.

Then, out-of-the-blue, after a workout at the Y, same problem: cranks great, no start. Starting fluid no effect.
Left in the Y parking lot, my grand-daughter would try to re-start it daily for the next couple days.
On day 3 or 4, it started instantly, she drove it home.
Parked, it sat the last 3 weeks. Today, starts instantly, runs great, but DO NOT TRUST IT NOW.

BTW, when it cranked great but no firing, no start - it never threw a code.

Could it be a flaky wiring connection somewhere?
I found & re-seated 4 large wiring harness connectors on the firewall over the fuse-box.
Are there other wiring harness connections I can unplug & re-plug a couple times to refresh possible flaky connections?
How about where does the crank sensor wiring merge with a harness somewhere?
Anyone with flaky wiring ideas? Or other ideas? Any feedback appreciated, best, Denny Ervin

 

Not familiar with the PT's electrics, BUT I've heard of fuse panel/TIPM troubles on these and a few other mopar vehicles. You could try lifting it and checking the modular wire harness connections going into the bottom of it for corrosion of the actual pin wire connections(not just the plastic multi wire plug connectors. and also check for CLEAN negative(ground) connections to the motor and the body. The eyelet ground connections tend to "tarnish" and insulate electrical flow, doing STRANGE things.