Depends on the state, really.
In NY, that truck would be "emissions exempt" and subject to a visual inspection. So as long as it had the original cats, it would pass. Even if they were hollowed out. And it doesn't matter if the CEL comes on
In NY, that truck would be "emissions exempt" and subject to a visual inspection. So as long as it had the original cats, it would pass. Even if they were hollowed out. And it doesn't matter if the CEL comes on