acceleration problems

[amikk97]

recently, my truck has been losing power. it starts fine and idles perfectly, and when I step on the gas in neutral/park it revs up but if I floor it it just dies out. when I put it in drive or reverse, its very hesitant to go, if I push on the pedal a little but it just sputters out. ive changed the fuel filter, and it worked for about a minute, then went back to sputtering out. I then took off the whole air cleaner assembly, and it seemed to run a little better now, but it still sputters out. I don't have bad gas, or at least I don't think I do, so im thinking my next culprit is the plugs may be fouled or the wires need to be replace, but if it starts fine and idles fine, could it still be the plugs? please help, im really stumped on this.