My Sirus radio seems to be getting "weaker" in that it seems to cut out more and more often as I drive.  Looks like some kind of sensitivity problem with the front end.  Always seems to happen in the same spots along the highway.  I haev sirus in my other vehicle and it doesn't seem to have this problem.

Is there some kind of adjustment possible?

i have it in my cars as well but i used the aftermarket version of it its not built into my radio. i would guess the antenna placement is not as good as with your other vehicle. i have also noticed i get better reception with it during the winter months when the trees have no leaves on them when summer comes back around and the trees start growing back their leaves i start losing reception in areas because of the dam trees being in the way.