Hesitation problem!
I had a primary O2 sensor go bad on the passenger side (used a GM part) shortly after the header install, should I go back and replace the other O2 sensor as well?
Could this be an opti problem or MAF problem?? Knock sensor problem?
I'm guessing at this point.
I've also noticed in the past few months that I am getting some valve train noise inside of the car, is this normal for LT1's?
My car only has 73k miles, mods are in sig.
Thanks for any help.

