[msisk6]

I live in a small Texas town outside of Austin. I think my diesel pickup is the only unmodified one here. It's really that common. The exhaust after-treatment and DPF systems are fairly complex and most owners just take 'em out. There's emissions inspections in this county, but diesel vehicles are conveniently exempt.

[alliao]

why do they take them out? and when do they take them out? when it broke?

[msisk6]

A bit late to the reply, but mostly it's perception: when the urea-injection exhaust-aftertreament systems first came out in 2013 or so there were a few reliability issues that dealers didn't do a good job of fixing. It's much improved now and my truck hasn't had any issues at all.

And, I'm sad to say, some folks just like the whole "rolling coal" thing and the ability to put out huge plumes of black smoke.