How do you know if youo need to have your MAF rescaled?
 

So I had a problem with my intake where the LTFT was very high negative at idle, good as soon as I got on the throttle. I thought I needed my MAF rescaled but now my LTFT is always in a good range after I fixed something and changed a few things. Do I need my MAF rescaled?

Is it just to fix bad fuel trims or is there something else it does too?

If the maf scaling was fine before the fault\leak then after you fixed the issues it will be fine

If ltft is say less than 5% throughout rpm range and afr and commanded afr follow each other within say 5% during wot runs then all good

OK, thx @steve990 My AFR and LTFT are looking fine well within range throughout the rev range. I'm running an Injen SP intake and even at idle it's doing a lot better now that I have figured it out.