97 vortec missfire
 

I have a 2wd ext cab shortbed silverado w/350.
it has a random miss fire code. It has true duels until it goes into the muffler, have no idea why, bought it like that. They have cats on both sides of the exaust and 02 sensors before and after both of them but the guy hollowed out one of them and the other still functions as it should. The miss fire has me stumped and im wondering if the two converters may cause it. Im just a dummy with lots of tools hoping to get pointed in the right detection thank u