2001 ford expedition xlt 4.6

My 01 ford expedition xlt 4.6 is acting up when I push the gas the engine revs and acts like it don’t want to go. It will hit 30 and doesn’t want to go. I’ve changed the fuel filter vacuum line ,cat converter , spark plugs I don’t know what else it could be when plugged up to a comp an o2 sensor comes up but that’s it what else could possibly be wrong? Plz help