[thstone]

The ECM detects engine misfire by monitoring the crankshaft speed and detecting variations/fluctuations in the speed. Engine misfire usually results in incomplete fuel burn. This rich condition can result in increased emissions and possible damage to the cat's, and thus, the CEL is illuminated.

Misfire across all 6 cyls generally rules out individual cyl components like spark plugs or coil packs and instead points to a component that is common to all cyls.

The usual likely suspects are the MAF or pre-cat O2 sensors but could be anything from a loose gas cap to a bad coolent temp sensor.

Drive it and see if the CEL returns.