the flashing light is coming from the rear lambda readout - it means the emissions passing through the cat is damaging it
but also a p0300 would trigger it as well as misfire will damage cats, they will overheat very very quick
http://www.obd-codes.com/p0300
it is quite accurate this article
i changed everything then found out it was the precat collapsed - look in engine chat and it is stickied 🙂
when i said get yourself a obd2 reader like the gendan interface you can tell us your kpa pressure in the manifold, engine load, throttle position at idle
kpa pressure will indicate air leak or faulty map sensor
engine load will indicate the above but also a blocked cat, faulty throttle body
throttle position at idle will indicate whether it is worn for example, i seen a 4% variance in throttle body positions at idle using different TB's
the flashing ecu will also pop up another code other than p0300, well it should do in theory as that is air / fuel related
