I know on a gertrag trans 6 speed , there is a cable adjuster on the back behind the throttle. Some times the connection there gets loose and has to be tightened back on to the bracket..it causes that exact problem. You may even have to adjust the cable tension , there is a orange looking button on the linkage for that. see other threads on the subject . it is well documented with many pics. Easy but annoying fix that cost nothing.rest easy.
SHOES ARE ALWAYS TIED, READY TO RUN