Me too, replace hinges
> I am having the same problem. How can you
> distinguish between a door alignment and bad
It is the hinges. That is why the door is hanging low and not wanting to close properly. If you pull up on the door as you close it, it will close properly, or at least more properly. Bite the bullet and replace hinges (~$90 from Motorsports Auto for both the upper and lower hinge assemblies.)
The door lock mechanisms wear out too, and if you really want it to close like new, without BANGING and CRUNCHING itself as it closes, replace the lock/latch assembly also.
The 77-78 Zs had a better mechanism located within the door, and the hinges didn't sag as much.