I ahve a 1994 Sonoma. The wiper does not seem to move far enough when in motion. Therefore, it leaves an unwiped patch on the drivers side which creates a blind spot. While in operation, the wipers seem to go a little too far down, slightly hitting the cowl. When off, the wipers do not seem to seat low enough. Also, you can move the wipers when they are off just by pushing them back and forth. Is there a bushing or something worn that needs replaced? Do I just have to replace the whole wiper motor to remedy this?