Diagnostic Aids
WARNING: This page is about a different car, the 2002 Pontiac Sunfire and 2002 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.
DTC P0133 or slow response is most likely caused by one of the following conditions:
- The system will go rich if fuel pressure is too high. The PCM can compensate for some increase, however, if the pressure becomes too high, DTC P0172 will set.
- A leaking or malfunctioning injector can cause the system to go rich.
- An output that causes the PCM to sense a higher than normal manifold pressure (low vacuum) can cause the system to go rich. Disconnecting the MAP sensor will allow the PCM to set a fixed value for the MAP sensor. Substitute a different MAP sensor if the rich condition is gone while the MAP sensor is disconnected.
- Check for a leaking fuel pressure regulator diaphragm by checking for the presence of liquid fuel in the vacuum line to the fuel pressure regulator.
- An intermittent TP sensor output will cause the system to go rich due to a false indication of the engine accelerating.
- Inspect the O2S for silicone contamination from fuel or the use of improper RTV sealant. The O2S may have a White powdery coating. This condition will result in a high but false voltage signal, indicating a rich exhaust. The PCM will then reduce the amount of fuel delivered to the engine causing a severe surge or driveability problem.