Additional Symptoms Tests: Surges/Chuggles
WARNING: This page is about a different car, the 2010 Chevrolet Aveo. However, it is still accessible from the selected car via links, so may be relevant.
Test the heated oxygen sensors (HO2S). The HO2S should respond quickly to a change in throttle position. If the HO2S do not respond to different throttle positions, inspect for contamination from fuel, silicon, or the incorrect use of RTV sealant. The sensors may have a white powdery coating and result in a high, but false, signal voltage, which gives a rich exhaust indication. The ECM reduces the amount of fuel delivered to the engine, causing a driveability condition.