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.

A restricted fuel filter can supply adequate amounts of fuel at idle, but may not be able to supply enough fuel during a heavy acceleration.
Water or alcohol in the fuel may cause a low O2S 1 voltage during acceleration.
Check for an adequate amount of fuel in the fuel tank.
When the engine is idling or at steady cruise, the O2S 1 voltage should vary from between about 100-900 mV. During the power enrichment mode, more fuel is needed and O2S 1 voltage should rise to greater than 447 mV.
Check for malfunctioning or plugged injectors.