My first BMW! Rear lift gate not working as normal?

[Charlieborg]

I just bought a used 2009 X5! Love it! The only thing I am having problems with is the rear hatch. I can push any of the buttons to open it and sometimes it opens normally, sometimes it just pops open but does not lift up? And it has only once closed by its self. I checked the latches on the mini tailgate and they click closed when I use my fingers to close them. Also checked the electrical/macanical connections inside the mini tailgate. It seemed connected and tight. Even unhooked it to see if it mattered.
Any suggestions?