Multitude of problems. at 80K the intake gasket failed ($1000.00) at 90K, AC compressor clutch failed ($800.00) at 100K front end work ($600.00) corosion everywhere. Way to go GM - NEVER again will I be sucked into your vechicles to purchase. I have a 1998 Honda with twice the km's that still runs, drives and looks new and worth 5x as much in resale.
Start with a clean slate - whatever your doing isn't working!