Ford Repair: 2000 FORD EXPEDITION 4.6L,2WD, mass air flow sensor, mass air flow

Question
I HAVE A 2000 FORD EXPEDITION 4.6L, 2WD.  WHEN I AM DRIVING AND WHEN I AM IN PARK, I PRESS THE ACCELERATOR AND THE RPM DO NOT GO UP.  WHEN I SLOWLY RELEASE THE GAS PEDAL, IT STARTS TO REV UP.  WHEN I DISCONECT THE MASS AIR FLOW SENSOR, THE TRUCK RUNS GREAT.  I REPLACED THE MAF WITH A NEW ONE AND IT DOES THE SAME THING.  IT RUNS GOOD WHEN THE MAF IS NOT PLUGGED IN.  WHAT COULD BE THE PROBLEM, I HAVE CHANGED THE FUEL FILTER, THE O2 SENSORS, AND THE MAF SENSOR. MY LOCAL MECHANIC CANNOT FIGURE IT OUT EITHER. ANY IDEAS WOULD BE A GREAT HELP.

Answer
Any codes? Off the top of my head TP sensor might cause this. When you replaced the maf did you clear the PCM and retrain the BARO???? If the original maf had a problem the PCM will be out of whack trying to compensate for an incorrect BARO or maf reading.