+1...Change the balancer. I also felt the rubber on the balancer and knew it had slipped. I removed the overflow tank and fan. Removed the belt and the pully on the balancer. Used a puller tool and got the old one off and then used the installer and put the new balancer on. Make sure you line up the notch correctly. It took maybe 45 minutes. Made a world of diference. Felt like I was driving a brand new car. Make sure you get the right puller and installer. The guy at Autozone gave me the wrong tool and good thing I looked it up on the internet to know that it wasn't the right one. Good luck. I wouldn't drive it much like everyone else said. Crank problems would be a lot worse!
I drove mine for mine for a few days w/ a bad balanver and It didnt mess anything up. But I didnt drive 200 miles. But mine WAS really messed up. Just change it and you should be fine. But dont drive it anymore.