I changed the cluth in my '93 F150 this past summer and now sometime if I hold the clutch in to long the pedal stays on the floor and the truck will start to move and I use my foot to pull pedal up and then I can push again and it works just fine. I drive and shift gears with no problem. The problem only exists when you let the pedal down to long.

Any help to straight this problem out would be appreciated

 

Possibly master cyl going bad.

 

im guessing it just needs bled. possibly the slave though.