2005 3.8L looses 1 quart of oil every 2000 miles. There are not leaks at all around the motor. A guy told me that oil collects on the back side valve cover preventing the oil from draining back to the oil pan. Anyone heard of this?

I've certainly never heard of that, but I would find it hard to believe that a quart of oil is sitting on top of one of your heads. More than likely youre just burning it off very slowly. I would just check it fairly often unless it really starts to get worse than you may have to bring it to a shop.

I just saw this...most of the series 3 3800 motors I've seen burn oil. Generally they lose between 1 and 1.5 quarts between oil changes I've noticed while working on them. Some of them are worse than that, there's one we work on that uses 1 quart of oil every 1000 miles. She's taken very good care of the car it's whole life and it's only got about 70,000 miles. I've yet to see any of them fail because of this.

bad PVC valve

If that was the case then the all the oil would end up in there and the pan would be empty.

a quart to quart and a half between oil changes is no concern.

I'm at 150,000, have same problem since 36,000 miles. 1 qt. down every 3,000 or every 30% on the oil life monitor. I add a qt., and I haven't had any trouble. (yet)

My car has the same issue. Just add a quart whenever it needs one, or is low. so far everything is ok.

Changing the PCV valve will help some, but my 04 Monte SS that I bought new has used a qt every 2-3K since delivery. Don't sweat it, just check the dipstick every weekend. Take 2 minutes.