The vehicle was runnig just great, then all of a sudden I noticed a severe lack of power under load. In WOT it just bogs and falls on its face. I have replaced all the usual tune up components: plugs, cap, rotor, wires, air filter and fuel filter, checked fuel pressure it is fine. The only code that came up was the o2 sensor, so I replaced it, cleared the code, check engine light went off and stays off but still there is no change. I unplugged each of the fuel system electronic compents one by one to force a check engine light, with no luck after reconnecting them and clearing the codes. The odd thing is that it will rev past 5000 rpms when it is cold.... but as soon as it warms up it seems to go into limp mode but there is no check engine light. If I pour fuel straight into the air flow sensor at WOT it will accelerate like normal. PLEASE ADVISE!!