stars.eg6

hi guys. i was on the dyno trying to somewhat tune my hatch the other day and it starts to lean out once in vtec. i have a 255 fuel pump, adj fpr, and 370 rc injectors. im trying to tune with a vafc for now. i was watching the fuel pressure guage under the hood during the dyno and it was running at 40 psi and once it hit vtec it would fall. ive done a search on here but everyone that posts their problem never say what they did to fix it. any help would be appreciated.