October 30: LEMON manuals on a temporary server, it is slow and having issues, download the manuals you need! Later in November we will switch back to the fast server.

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