'96 Lumina 3.1 - Jumpy shift in OD when hot

I have a 96 Lumina with the 3.1. When the car is warm, it shifts really hard starting from a full stop when in overdrive. It doesn't really do it in the winter time unless I'm in heavy traffic and the car has had a chance to get warm, and it doesn't do it when I'm in 3rd. It's been this way for a couple years, but this spring it's already starting to get worse than it has been.

Do you guys have any idea what my problem is?

P.S: Could this possibly have anything to do with a 'camshaft position sensor' error code that just popped up the other day?

The shifting problems sound like a bad pressure control solenoid in the tranny.