One problem related to front suspension lower ball joint has been reported for the 2001 GMC Sierra. The most recently reported issues are listed below.
Many problems: 4 wheel drive sensor, front end suspension, parking brake, service brakes, anti-lock brakes, speed sensors, radio, center console, engine noise rapping when starting, tailgate cables, anti-theft sensor, and now the battery voltage gauge needle excess dropping when stopping, engine idling to low when stopping. Dealer says problem is normal. Let's test drive a new truck and show me it is normal. This truck is a lemon in my eyes!.