I just recently bought an 05 g35 5at, and the previous owner decided to cut the cats and put in these nasty looking pipes in. They took the o2 sensors with them, so I was wondering if the o2 sensors affect the afr. And would it cause the car to be sluggish. I was messing around and it was running 0 to 60 in around 19 seconds. I was thinking either it was the sensors or it could be worse and be the torque converter, but I wanted to look into the sensors first.

 

Do you have a check engine light on? I would start there

 

Yes but they're only for the o2 sensors, and I didn't think the o2 sensors would cause that much of a problem, but in used to working on older shitboxes

 

Are the codes for the upstream or downstream sensors?

 

I'm pretty sure its for the down stream ones, I'm pretty sure I have the upstream ones still in place, although I need to check. But I know for a fact I don't even have the second ones plugged in.