that actually sounds like a bosst cut to me.....i had that similar problem a while back when my vaccum hose came off.....so checking all your vaccum lines could sort that out....
if not then also take your cooler core and get it pressure tested as a dent could have punched the core and now its either leaking air or leting in unfiltered air....
if you say you have a aftermarket fuel pump then fuel shouldnt be an issue but get that checked as well.....most of the time a good dyno tuner will be able to pin point where the problem is arising from and should be a easy fix at times....
good luck with it all mate and let us know how you go