so i put a full exh on my car when i did i just removed the rear o2 sensor and bolted up the hole. not to long after that my car started runin a bit rougher. i read somewhere before i took it out that it was just used to prevent the P0141 code, is this true? would the rear o2 sensor have anything to do with A/F or anyting that would cause my car not to be runnin the best? should i put it back in?

 

Put it in and run a "CEL eliminator" (a drilled sparkplug spacer). If that doesn't help then you gotta start tracking down the problem.

 

^ doesent that just turn off the check engine light?

 

If you just removed the rear O2 then your car isn't getting the signal difference between the front O2 and the rear O2 that it needs and will put your car in "limp mode". By using the CEL eliminator you still get a signal from the rear O2 but it's not seeing as high of a gas reading as if it were in the direct stream so it "thinks" the cat is still working correctly and doesn't throw a code resulting in the "limp" mode.
Make sense?