Hey, Dan. Looks like I'm right up the freeway from you, in Cedarburg! Anyway, I'd maybe look at the wiper transmission assembly to see if something's loose or worn. I know there were some wiper motor problems on the earlier GP's, but I don't think that's your problem. The transmission is the linkage assembly, underneath the long black plastic cowl cover at the bottom of your windshield. You'll have to remove the wiper arms, and then some plastic fasteners to remove this cover. Hopefully then the linkage will be exposed, and you can look at all the pivot points, etc. to see if something's loose or bent. It's hard for me to say what exactly is wrong without actually seeing it, but this is where I'd start. Good luck...
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Adam Smittkamp
ACS Automotive Service, Inc.
*Your ACDelco Headquarters*