i have a 99 Chevy Malibu and my belt want stay on ever since i changed my belt and power steering pump pully and i notice that my tenisonor pull was on backwards and i know the power steering pully is on all the way and i know i have the tenisonor pully is on right and all the pullys look like they are lined up and none are locked up does anyone have anyadvise or might know wat is wrong

 

Welcome to the forum...
Check and make sure the replacement belt is the correct size...too big of a belt and it won't stay on...
Your owners manual, if you have one should list the part number for the belt..
If it is the correct size belt, you may need to check all pulleys and tensioners for loose or worn bearings... there should little to no side to side or lateral movement for the pulleys and tensioner...