When I drive my car a 2003 infiniti g35 and shift for about 15-20 minutes the clutch gets stuck and I have to pull it up with my foot and it is hard to get into first and second and nearly impossible to get in reverse, I read adjusting the clutch pedal may help any suggestions on what it could be (has new clutch and slave cylinder).

 

Bleed the clutch, if there's no air in it wait until you can reproduce the issue then verify that the clutch operating cylinder still works by visually inspecting it. You can do this from the side of the vehicle with a good flashlight and an inspection mirror. If the slave cylinder is still operating then the pressure plate may have failed and only starts to show problems once the springs have become heat soaked. I suspect you just have air in the line, did you purge the clutch master cylinder on a bench first to get air out of it or did you just bolt it on and go without any pre-purge operation?