i replaced my exhaust manifold on my 98 civic dx because it cracked (i guess there known to do this according to the dealership) so i picked one up for like $60 stainless, my check engine light is still on, i dont have a cat amore and i have 2 sensor before and after cat, so its messing up it hessitales and goes in and out when first drving plus gas mileage should be way more with my other mods done. i was going to replace both o2 sensors but the problem probably will still be there. So does anyone know if someone makes a dummy plug that will tell my computer that its stills has a cat, so i can get my car running right again, any help or idea would be greatly helpful..thanks