Hi All, I am DESPERATE for help please.

I've never had a car I couldnt fix..... until now.

The car runs okay for a while then all of a sudden starts to sputter and misfire. It trips the engine light and the EPC and sometimes the traction control, but not always. I've changed everything I can think of and its costing me a LOT of money without success. I( scanned it and the codes said throttle body or pedal sensor (which were both replaced. I replaced the following:

Fuel sensors (High and low)
Injectors
Plugs
VVT Solenoids
Maf Sensor
Throttle body
Throttle pedal (whole unit)
Relays undr the ECU
cam position sensors
and a bunch of cooling stuff

The car would start okay, and run for 30-50 miles. then will all of a sudden trip lights, go into limp mode, and will be almost undriveable. Sometimes if I turn it off, and back on, its fine again for a while. I'm super desperate for any help. Car has about 150k miles on it. Its a 2007 3.2 that my kid use for college. Any help would be appreciated.