Okay so about a month ago I did the FWI and about a week ago had the resonator cut off. Someone told me I should undo the battery and let it set to kinda let the PCM re-learn its self. Since I am getting WAY more air flow.Its not a big deal and I did it...I dont understand what it did or if anything. So question is does doing that really re-learn your PCM? And should you do that with new small mods you put on ur car?