Try a few things to isolate your problem. 1.If necessary adjust your track brackets so there is about a 1/4 to 1/2" play between the door and track at any given spot,and make sure your tracks are plumb. 2.Clean your track and lube it w/silicone spray,lube your rollers,hinges,and pulleys. 3.Have someone check and adjust your torsion springs(they can be dangerous). 4.Clean and lube the garage door opener chain w/wd40. These things are excellent routine maintenance even if your not having problems,but if your problem persists it is your opener..hope that was of some help!