I have a 2000 Z28 A4 with 82k on it. I recently changed the plugs, wires and as of last week coils. My car is throwing 3 codes! Someone please help me...

P0131
P0300
P1637

It is creating my car to run like crap and its getting nice out and I want to drive it.. Any help?

 

P0131
Oxygen Sensor Circuit Low Voltage
(Bank 1, Sensor 1 and Bank 2, Sensor 1)

P0300
Random, Multiple Cylinder Misfire Detected

P1637
Generator L-terminal circuit

What all did you remove when you did this maintenance? Have you tried unplugging the negative cable of the battery for a few minutes, then try restarting the car?