Here is some info that may be useful to someone else:
Last summer my wipers started working wierd, periodically they would slow down and then speed up again. At the worst of if I had to turn them on and off to get them to move by an inch and had to help them along to go through the cycle.
I assumed I had a bad motor so off to the shop I go and buy a new motor assembly for approx 150$. Replaced it and the exact same thing was happening.
After troubleshooting further I found the problem to be with the arm mechanism that drives the wiper arms. The passenger side's shaft bearing was ceased. Had I known what the normal condition of the mechanism was I would have found this out simply by disconnecting from the motor and trying to operate the mechanism manually. I assumed it was normal to have some resistance.
Anyway, long story short, the dealer wanted 450$ for the arm assembly/motor combo (only way it can be bought new) so I got an arm assembly from a scrap yard for 75$.
Replacing the mechanism was a job because of the difficulty in getting the thing out once you've detached it but other than that it was ok.
Hopefully this can help someone find the real problem before spending money on a motor that may not be the issue.
Robby