Moon roof problems on 2003 Oldsmobile Alero

Sometimes the moon roof does not open all the way. Sometimes it does. It'll stop half ways at times and sometimes it only opens 1/4 of the way. It is very erratic and there does not seems to be a pattern as to when it is happening. Any ideas?

Asked by for the 2003 Oldsmobile Alero
I see a sunroof motor available at buts its very expensive and the labor the replace this is 2.2 hrs, maybe try some WD40 first to see if it just needs lubrication.