Hi, I am swapping a 1993 4.3L out of a safari van into a 1990 4runner. I want to dual the exhaust but I am not sure what to do with the o2 censor. Factor the engine only has one censor where the exhaust comes together into one. After separating the exhaust how do I hook up another censor? Do I just choose a side to put the censor? how much would get screwed up if I leave the censor un plugged? Thanks.

I did the same thing i just moved my o2 sensor on my driverside exhaust manifold! The plug in runs up there anyways. Trace the wire from your existing o2 sensor and plug the new one in at the manifold.

True true. I would run an H or X pipe anyways with true duals to balance the power and sound. But there should already be a bung for your O2 sensor on the exhaust manifold. Either way will work and it's best to leave your o2 sensor plugged in!