Tried the WD40 approach and aside from making the cabin smell like WD40 no noticeable difference. I have noticed they almost jerk across the windshield ever so slightly. That makes me think its the windshield wiper transmission.mswerb said:I have noticed the same thing on the rear wiper of my Chevy Equinox. If I don't use it for some time it will operated SLOWLY. I hit it with some WD40 and it works just fine. I'd try this before tearing into the wiper motor.