Governer sticking? Posibly the bowden cable pressure valve sticking. Aint seen that one yet. If you can get your hands on another v/b for free it might be a worthwhile swap just to see what happens. You also could try pulling the governer and checking it.
Project Smoker, '87 603 powered wagon
Hauler, 96 CTD can you say torque?
Toy 73 Cougar xr7 convertible
Acme Automotive Inc.