Diagnostic Aids

DTC P1133 is most likely caused by one of the following conditions:

• High Fuel Pressure
  
  System will go rich if fuel pressure is to high. PCM can compensate for some increase, however, if fuel pressure becomes too high, DTC P0172 will be set.
• Leaking Injector
  
  Leaking or malfunctioning injector can cause system to go rich.
• Manifold Absolute Pressure (MAP) Sensor
  
  Output that causes PCM to sense a higher than normal manifold pressure, indicative of a low vacuum, can cause system to go rich. Disconnecting MAP sensor will allow PCM to set a fixed value for MAP sensor. Substitute a different MAP sensor if rich condition is gone while sensor is disconnected.
• Pressure Regulator
  
  Check for a leaking fuel pressure regulator diaphragm by checking for presence of liquid fuel in vacuum line to regulator.
• Throttle Position (TP) Sensor
  
  Intermittent TP sensor output will cause system to go rich due to a false indication of engine accelerating.
• O2S1 Contamination
  
  Inspect O2S1 for silicone contamination from fuel or use of improper RTV sealant. Sensor may have a White powdery coating, which may result in a high but false voltage signal, indicating a rich exhaust condition. PCM will then reduce amount of fuel that is delivered to engine, causing a severe surge or driveability problem.