have hydraulics checked if yo have that or check adjustment and if ok you'll need a clutch

Check the cable for fraying (strands of cable separating) at the transmission end and under the dash where it hooks into the pedal.

If that is OK, check for a loose connection at the firewall (in the engine bay where the cable goes INTO the car). The cable slides
into a metal tube that is connected to the pedal cluster... these tubes can come loose and cause issues.

Picture attached.

Thomas