Hi Don; Sounds like you're on the right track. I don't know if the 68 had a
return spring on the pedal. If there should be one, and it is missing, that
could explain everything. It is also possible to add a spring to pull the
pedal up, if only for a test.
I added a spring on my 67 Crown. A universal throttle return spring works
fine. It hangs from the steering column & attaches to the pedal. It is up out
of sight.
Larry
67 Crown 4 DRHT