+1 Fresh cables and housings, even though those bits are probably not the problem. Fresh cable and housing will cost all of $3 or $4. And a cable problem could be your issue.
Sounds like the spring on the derailleur is shot, since you cleaned it already. The Light Action was a good, but low end derailleur. You can find a replacement, or use something better, like a 105 or 600 from that era.
Does the derailleur snap back if you disconnect the cable? Work it by hand, with the cable disconnected from the derailleur. Push the derailleur inward, then let it snap back. If it quickly returns to the high gear position, then your cable is the problem. Watch your fingers.
If you end up installing a replacement derailleur, I would change the cable and housing anyway. So the small investment in cable will not be a waste.
Last edited by wrk101; 09-04-11 at 08:00 AM.