Well, the only code shes throwing is for my bad maf which has been bad for a while now and hasn't affected my mpg before (replacing it later this week hopefully). Other than that she does have a leak which I haven't addressed yet (thinking its the res flange). how do I go about diagnosing this? I have torque app and can read anything needed

Also, I'm seeing about the same amount of kr as I did with stock exhaust....I'm guessing I didn't make enough room for the front o2 (banged it till there was about 1/2" clearance) and its false? from what I've read I should be seeing 0 kr on a stock engine with headers