P CODES (POWERTRAIN) P0800 - P0899 P0871 Questions

I Am Having Several Problems And I'm Not Sure If They Are Connected. When Cold, The Car Wants To Start Hard. It Will Crank And Roll...

Replaced Crankshaft, Cam Shaft, O2 Upstream And Atc- Transmission Sensor And Still Getting Codes Of P0016 Shows Same Code Of P0016 Two Times...