Its your clutch pedal. I had the exactly same issue. Its known issue where nissan released an updated clutch pedal and bracket with a beefier tac welds and bracket. Initially i removed the pedal and took it to welding shop to reinforce the tack welds. Well it helped tremendously, but over time it just went back to not functioning properly. Yes it drives great, and i had to push the pedal back up, even cruis control can be affected. The remedy is to either remove your existing pedal and re weld it and it will be better, or buy a new clutch pedal. Pedals are about $120 bucks. And almost discontinued. Its a pain in the *** to remove because the same and ur sorta working upside-down, but totally worth it. Im no mechanical, but it takes 15 minutes to remove the pedal, and took my another 45 to align the bracket and pin down there.