Cary,

The oil light comes on at 3 psi, your pressure is much too low for 2000
RPM where it should be at least 10 or 15 psi.  Check to be sure the
sender wire is not shorting out on the engine some place, and then try
changing to 20w/50 oil, mineral oil only.

Fuel dilution from worn rings, a poorly running engine, or excessive
fuel pressure can thin the oil to the point the pump can't build enough
pressure.  If the heavier oil doesn't do it you need a new engine, and
do it soon or you risk destroying this one past the point of rebuilding
it.

Good luck!
--
Stuart MacMillan
Manager, Case Program
800-909-8244 ext. 8208
Fax: 206-269-6360

Getting your share of the Net yet?
http://cobaltgroup.com
http://UsedEquipNet.com