LaserJet IIIp gone berserk

I have an HP Laser Jet IIIp that prints fine if I just
ask it for one page, but if I try to print a document of
more than one page, it will print the first page fine,
then it just cranks out page after page of blank sheets
and finally, a second page then again to the blank sheets
etc. Anybody else encounter this one? If so, how did you
fix it? Is it a printer spooling thing?