Problem

[icepac]

look at the number of cats. the more cats, the dirtier it runs. verify by removing an ot sensor, or otherwise tapping into the exhaust before any of the cats. you'll be surprised.

I'm an emissions inspector and engine management specialist so I do this for a living.

So which engines are these "dirty" running engines?

[CAP1]

I'm an emissions inspector and engine management specialist so I do this for a living.

So which engines are these "dirty" running engines?

so do i. look up a few posts. and to answer your question, no they don't run dirtier. they just don't run significantly cleaner either. 4 cats are not required due to obd2 either