Start by flushing clutch fluid completely and see if that resolves it. When I did this last, I basically drained and filled 2x in hopes of removing all the old fluid and it seemed to work nice. If that doesn't resolve it, look into leaks, lose pedals, and master cylinder failure.

 

I’m having the same issue but it’s opposite. I changed my clutch and now my pedal comes back up half way . I changed my slave cylinder and it’s still doing that but after a while of driving the car my pedal gradually gains more pressure and it never actually fully goes back to normal. What should I do. Please help . I bled my clutch already and still the same thing

 

Sounds like you're not bleeding it properly.

 

I had the same issue. It was more prevalent when the weather was hotter. I replaced the slave cylinder from AutoZone (lifetime warranty) got the Z1 stainless, wrapped line, then wrapped it in titanium exhaust wrap and replaced the fluid. Feels better than ever now.

 

Did the issue ever return for you?

 

Number 1 reason for the clutch pedal not returning is air in the lines or old fluid. Number 2 would be a failing master/slave cylinder.

If there's not enough pressure pushing back on the pedal when you release it then it won't push the pedal past the fulcrum point when the assist spring does the rest of the work to make the pedal lift back up.

Basically how it works, the spring helps keep the pedal fully disengaged AND fully engaged. You just have to make it past the halfway point of the pedal travel and the spring rolls over a cam on the pedal hinge.

1st half of pushing the pedal you are fighting the spring, 2nd half of pushing the pedal the spring is assisting you to push. Same works in reverse, clutch pressure plate pushing on the TO bearing pushing on the clutch fork generates pressure in the hydraulic system that pushes the pedal back up and it's fighting the weight of the spring until the pedal hits the halfway mark. Then you're past the top of that cam and the spring snaps the pedal fully back up to the released position and holds the pedal in the uppermost position.

Without a spring you would always have the weight of the pedal putting a tiny bit of pressure on the TO bearing which would prematurely wear it out, however Nissan uses a very stiff spring and an aggressive cam that removes ALL pedal feedback so the pedal always just feels numb. Aftermarket pedals like the RJM don't use a cam and instead just use a light spring to keep the pedal disengaged.