1994 Ford Ranger clutch intermittent problem

hi my 1994 ranger sat for 3 yrs i got it running great drove it around all morning had emissions check done wich it passed then the clutch would not disengage when it cooled down it worked again did it again when it gets warmed up when i pump the clutch pedal problem goes away im nervous to drive it like this shifts fine otherwise just when its hot cant take off from a stop clutch wont disengage thanks