2 things to check, nuetral safety switch adjustment and tranny mount wear. The mounts will callaspe allowing the tranny to either rise or settle in park on hills, this lets the shifter push or pull the arm slightly, sometimes enough to cause the "p" posistion to go open.
Project Smoker, '87 603 powered wagon
Hauler, 96 CTD can you say torque?
Toy 73 Cougar xr7 convertible
Acme Automotive Inc.