With the van in park or N whenever I rev the engine it starts to hesitate.

I would check the Oxygen sensor. It sounds like your engine keeps switching from running too lean to running too rich. Good news is it's fairly inexpensive to fix.

i would have the fuel pressure checked and the cat converter checked. either one would cause this. Roy

You have throttle by wire. the computer controls idle and accleration based on where the gas pedal is at. You most likely have trouble codes in the PCM concerning this problem. You need to get the car scanned by a real diagnostic scanner, not a generic OBD 2 code reader.