Kerosene exhaust smell

[BULLETPROOF4.9]

I have a 96 EB Bronco 5.8, which i've modified the exhaust on. It's straight duals down the passenger side, with glass packs only, no Cat. When I let off the throttle, I get a strong kerosene odor from the exhaust, is this just because of the lack of a Cat and it running fat? Any ideas would be helpful.

[BULLETPROOF4.9]

I may have answered my own question, and you all may be able to confirm it. When modifying the exhaust, I "rigged" the O2 sensor by cutting out the bung from the old pipe and temporarily drilled a hole in the new pipe and self tapped the old piece onto it until I could get a proper bung welded on and the O2 reinstalled. My guess is that this is why it's running fat and has a CEL.