No downstream O2 sensor
 

Bought a 2004 1500 hemi with the cats already removed. Whoever removed them also cut out the rear O2 sensors. The connector clips are still there (dangling) but nothing on the pipes. So the non foulers are not an option. Any other option for getting rid of the engine code light?

Buy some O2 bungs, weld them in place and then use the non-foulers

The question is , did you gain any power or fuel mileage by eliminating the cat?

Generally you're not going to get better mileage. You might get better performance as the exhaust becomes less clogged/restrictive but it certainly will make it sound better if that's what you want.

I do not have cats on mine.