I put long tube headers and ory on my car and didnt put the o2 sensor sims in. I just put the o2 sensors back in the bungs at the bottom of the header just to stop it from leaking. bout a week running my car like this my car has been idling funny i tried putting seafoam in but it still does it i was wondering what u guys think it could be .

 

ok you have to get xtensions for the front O2's and they go in the header. the rear O2's get the simulators. you have to have the front ones hooked up becuase that is how the computer knows when to + or - fuel. the rear O2's have no affect of performance just the SES light will come on.