My friend had the same symptoms on his canyon and it turned out to be the cam actuator that was at fault,would it make sense?

 

Flashing check engine light usually means one or more cyl. are misfiring. The rate of misfire is high enough to damage the catalytic converters. Codes should tell which cyl. is(are) misfiring... The "Air, Fuel, Spark" approach here may not be applicable here. PCM would "know" what's going on better.

Thanks.