I had a similiar problem with a Sony CDU4821 (oem) CD-ROM drive ............. it seemed to operate too fast (opening and closing) and the tray seemed to actually bounced a little when fully open, then would close so fast, and unexpectedly that I scratched several of my cd's (not fully loaded) .... one of them actually was still spinning when the drive opened and that disk was a Win2K os disk!
The Sony was used in several different systems, but was only about 1 1/2 yrs. old and not really abused at all (no games)!
I never really found out just what was causing the problem ................ I flashed to a new mb bios and re-installed the os and it seemed to help some.
The best advise I can offer is to just get rid of the drive, I still don't really trust my other tray-CD-ROM drives as a result of living with the problem Sony for too damn long!
I don't use "Sony" drives anymore and prefer the Pioneer 106S - Slot load DVD-ROM - NO damn tray to deal with!
One thing I never do anymore with a tray drive is to push in the drive by the tray when closing it ......... I always use the button ....... don't want to take a chance on another tray going bad.
Sorry I can offer no help ......... just empathy ......... trash the problem drive!