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So i have a 05 civic special edition coupe, otherwise known as the american dx from what im told. Anyways i had it to the dealer for a valve adjustment, while getting this done the dealer noticed i had i cracked manifold that needs replacing.

I've searched the site, and this seems to be a common problem. And rather than fork out a grand for a new oem manifold, im going to go with a 4-1 header. I know that this gets rid of the cat, which isn't a problem where i live. My question is without the cat and a aftermarket header will the car throw a check engine light? I know it has the o2 sensor holes in most headers but is there anything otherwise i should know?

Mark