Exhaust

Was looking at my truck exhaust and I see that there are 4 cats on it and the 02 sensors are in between the two on each side I was curious if I cut the back ones off would it throw a code or would it cause me to fail an emission test or would it be fine?

 

Pre cat measures your air fuel ratio and post cat measures catalyst efficiency ....so yes a code would be thrown

 

won't throw a code, and unless you're in Commufornia you'd probably be fine with emissions.

That said, it would only be for sound. There is no benefit to removing em.

How many miles on your truck?

 

My last car had 4 cats with 4 sensors, the rear 02 sensors were in front of the secondary cats. I replaced the secondary cats with test pipes and occasionally my check engine light would come on, I would just clear with my scanner. After the cat delete I noticed that my rpm's would rev faster and the acceleration of my higher speeds definitely improved.