Can a 2002 Chevy Silverado Z-71 run on E85?

No, a 2002 Chevy Silverado Z71 did not come standard with an engine designed for E85 fuel. While some flex-fuel vehicles were starting to appear around that time, they were not common and certainly not standard on a Z71. Using E85 in a vehicle not designed for it will likely cause damage to the fuel system and engine.