What could this be: Back firing through intake when you press the gas more than 25%; revving it up and you can hear the car suck in air as hard as it can, almost dies until you let off of the gas, then when you let off, it revs up. You can hear it miss when it revs up. This is on my 6 cylinder by the way.

 

yes, it is a lean condition since you are backfiring through the intake. are your injector values correct? is your fuel pump having any problems/filter clean? these are probably the first things i would check. if it is running fine till you give it some throttle, it sounds like more of an issue between the pickup of the pump and the injector itself, not a tuning prob. i don't know for sure.