Ok got a 93 Del sol Si w/d16z6. I put my stock exhaust manifold back on and now I am throwing a code 43 and a code 1. I'm thinking either I over tightened it, or the wd40 on it that burnt away after it warmed up messed it up. Could it also be the octane boost I have been running...I ran one tank with old header in and no prob, then filled her up again with more octane boost and drove down the street to my house (about a mile). After the motor cooled I swaped over the old mani. and o2, and thats when I started throwing the codes. It only throws the codes after its out of open loop. What should I do fellas???