2002 Chevy Silverado 242k with 4 speed automatic. Done basic tune up and fuel system update: spark plugs wires, cap and rotor. New fuel pump , fuel pressure regulator. New upstream sensors , mAf sensor ignition coil. New calve cover gaskets & intake gaskets.

 No codes but live data shows running lean adding 15 %
runs great in closed loop but misfires in cylinder 3 mainly during idle in closed loop. Running out  of options 

stalls at idle

is my engine shot? Or is it a computer / electrical issue? 

thanks!!