Flashing engine check light...misfires?

[Redline Motorsports]

I have had a couple cars with flashing engine check lights that leave no DTC codes. Does anyone know the defined answer for what GM is trying to let us know is the problem without any clues? I think it's misfire related and even killing 0300 mil light doesn't resolve it. Maybe if it is misfire, the tables need to be moved closer to 32767. Any thoughts?:nixweiss:

Howard

[ChipsByAl]

Howard disabling the code P0300 does eliminate the code from setting and turning on the light (after the condition improves) but has nothing to do with the SES when misfires are occuring. The SES light will flash when the PCM senses a situation that can damage the catalyst.
You are correct with moving the misfire tables closer to 32767 to dampen the flashing light. I would recommend only moving the tables what is necessary and not maxing them out. If you have a true misfire you will not be able to scan and see which cylinder is misfiring.
AL

[minytrker]

I had a car on the dyno the other day do this. It was a vacume leak around a injector. The owner just had the fuel rails off and didnt get all the injectors seated right. I also have seen a blazer do this on the street when a spark plug wire was barley off. Both cars only did it at wot around 4000+rpm.

[Redline Motorsports]

Makes sense...this car has a big stick in it and idle is quite rough at low rpms. I only seems to happen after a hard throttle event which is follwed by and idle situation. Maybe raising the idle/low speed sensitivity up and leaving mid to high rpm alone might stop this. Any way to log this to confirm its existence?

[ArKay99]

This happens to me occaisionally when starting from cold and trying to move the car a little before it's fully warmed up. I suspect it's from too much fuel charge going into the exhaust. It only seems to happen to me at idle and not fully warmed up.

[Redline Motorsports]

There has got to be an exact reason for the blinking light. Not much of an OBD tool if it doesn't give you a clue?

Seems to happen after hard driving and the idling.

[minytrker]

I found both problems with the blinking light only after doing the F2 or F3 (dont remember off memory) on each car and watching the scanning software while someone else drove. I still think its something missfire related.