The reason I ask this question is because I have a BCRH installed now and around ~8000 rpms I get a backfiring/sputtering type of noise. I know that a header usually causes an engine to run a little bit leaner, but I thought that the computer adjusts for this. If it isn't a lean condition, what else do you guys think it might be? Also.....everything seems to be in order (install, condition of header, etc). No other mods, except a Tanabe axle-back.