Thread: OBD codes P0420/P0300- little/no power past 4th gear, fuel in oil, sulfur in exhaust

Originally Posted by timeshhift

I'm aware the cat is bad, I'm wondering if the fuel in my oil is the cause and what the cause of that might be. The sulfur smell is only a recent development. I was led to believe unburned fuel is what makes the cats go bad in the first place.

Originally Posted by Turbocharged400sbc

with manifold air pressure being higher due to an exhaust restriction the pcm will add extra fuel as it thinks your under higher load, cylinder washdown and extra fuel in the oil is an effect, not the cause

This^