The CD player in my car sometimes picks up where I left off when I get back in the car other times it starts the CD from the very beginning. I checked set-up and cannot find anything that would affect this. Does anyone else experience this?

 

Different recording standards on different CDs.

 

The last time it happened was with the same CD, once starting at the beginning, next time where I left off.

 

Dirty CD, or dust in the head unit on the laser optics.

Is this a mass produced CD, or a "homebrew" burned on your computer?

CD's recorded or burned at home are less stable and apt to degrade after exposure to the temperature extremes in vehicles, that can cause skipping and other odd behavior.