Misfire or Rough Running

CHECK:

1. Fuel Injector
2. Contaminated Fuel [1]
3. Fuel Pressure Regulator
4. Manifold Absolute Pressure (MAP) Sensor
5. Exhaust Gas Recirculation (EGR) Valve
6. Electronic Control (ECM) Unit

NOTE: The system that could be the source of the symptom are listed and should be checked in order, starting with #1.

[1] Fuel with dirt, water, or a high percentage of alcohol is considered contaminated.