My tensioner pulley is kind of vobably (doesn't stay even), I was wondering does anybody know how to fix it?

 

teh tensioner may not be completely seated with respect to the bolt...it has to fit completely into the slider groove and allow for ease of motion up and down with NO BELT wrapped around it...I would start there...plan on replacing the bearing set in the pulley if it binds up and gets caught...belt will suffer too...