I don't think you are supposed to change your FP. Leave it around 38-42, vacuum off. I believe someone posted that with too low FP, emissions can go up. Make sure you have changed your oil recently as well. I would run just pump 93. Mine passed with flying colors on 50's with a Casper street chip and 38# FP on an IM240 dyno with a 3" cat (new and only used for emissions every other year).