Wipers on my wagon have annoying and mildly alarming jerky motion as they go back and forth, as though there is play in the drive system somewhere and it builds tension, launches them two inches, then they wait for the tension to build-up again, move again, repeating this motion about 6-8 times in each stroke upward (and again downward). Most noticable at the slower constant wipe setting. Also, the passenger-side wiper is contacting the lower corner windshield trim with a knock on each stroke (new noise).

Overall, the wiper rates are normal, intermittent works fine, no blown fuses. The motor is growly but works fine (for the moment). Is this a motor problem, linkage/cable problem, or both? I've searched the RWD index without finding mention of how to approach this particular problem. Trying to be proactive and avoid the wetheaded drive home...