I have the Same problem

This was an intermittent problem for me. Usually I "fixed" the problem by rowing the shifter and if that did not work, time, (or having it towed to a mechanic) usually "fixed" the problem.
I currently have the JP GC in a dealer - they Claim the PDC (power distribution center - aka. main fuse box or engine fuse box) is corroded too bad.
I am currently trying to locate a used PDC - since the dealer claims this is not longer available from D/C/J - and claims is not available thru aftermarket sources. Contact me (a) if you have success or (b) need help locating a PDC. mark_a_lucas37@hotmail.com