[spudracer73]

if the engine light blinks when the car is running, it means that there is a misfire bad enough to cause the catalytic converter to be destroyed. when i was in college for automotive technology this was one of the big issue we tapped on. we would induced a bad misfire and do all sorts of diagnostics with different tools ranging from spark testers up to osciloscopes. i am not trying to be a know-it-all, just wanted to give my opinion. any way, any books about emissions will give you this info.