July 1: So it begins. Don't worry, this is not in the correct legal jurisdiction!

O2 Sensor Symptom Diagnosis

Runs Rich

Fuel in Oil
Evaporation System
Main Relay
Fuel Pump Relay
Stuck Open Injector
High Fuel Pressure

Runs Lean

Vacuum Leaks
Clogged Injectors
Stuck Closed Injector
Low Fuel Pressure
Water in Fuel