Just wondering if you could have a bad cat without the check engine light on? I know the cel works cuz it lights up when the key is in the ignition after the first turn and i know some people sell their cars after they break the cel light and say it doesn't have a cel light on lol. that's why you gotta check first but anyways, feel like my cat is bad cuz there is hesitation when accelerating and after driving for awhile the car stinks and minor white smoke is coming from exhaust. I currently have no cel light. D15b1, 1991 honda civic hatchy. Oh yeah also can you bolt on the cat or does it have to welded on? I looked under and saw two bolts on one side but not sure, i know i'm a noob but thanks guys for reading.