The garage door doesn't close all the way. It stops at about an inch off the ground and then the garage door reverses as if it's hit something. Problem is there's nothing there!!

I tried adjusting the limit screws to make the door actually make contact with the ground but it seems as if the limit screws are almost binary. Either the garage door stops an inch from the ground and retreats, or the garage door hits the ground and attempts to keep going for half a second before pulling back up. No, I'm not turning the limit screw a lot. I'm maybe turning it a 16th of an inch and I still can't find the happy medium between smacking the ground and not even making contact with the ground.

I've been playing with the limit screw for a few days now and cycled the garage door at least two dozen times so far, so I feel that perhaps the limit screw isn't the issue. Could it be the spring that's giving up the ghost?