Can anyone tell me what does it mean if my civic DX is FLASHING a Check Engine Light? It's a 2000 civic DX w/ the EX Exhaust manifold. And yes i do have both the DX O2 sensors in the EX stock header. It was welded in by a muffler shop.
Any response is appreciated!

 

Might be misfiring. Short out the blue connector in the passenger side kick panel.

 

If your just driving along and all of a sudden the CEL begins flashing at you, that is indicative of a misfire.

Can you pull some codes?

 

are u running no cat? i saw no mention of it? an ex cat is a direct bolt on along with the manifold u already have. if u are running the 2nd o2 sensor without the cat that could be another reason for the cel.

 

If Misfiring is the problem, what can I do to fix it? I gotta mention it flashes ONLY when it's in idle and idle really shitty. Sometimes it go low as 300rpm and normally its suppose to idle atleast 800rpm.