Any hope for you? I have done a lot and replaced TB and cleaned it and code comes back every now and then, don't know what to do, i have a 03 g35 coupe

 

This code isn't specifically for the throttle position sensor, it's a code saying the target signal between the accelerator pedal/gas pedal switch (APP) doesn't match the actual value of the throttle body position sensor (TP).

This can also be caused by a faulty APP, if it has two inversely proportional rheostat switches, if one of them starts to fail it tells the computer a slightly wrong value, then the ECM makes the correction to throttle but the TP data now doesn't directly correspond to the APP data.

That this is an intermittent issue and you have already replaced the throttle body makes me strongly suspect your APP is intermittently failing just slightly.

You can buy just the sensor instead of the entire pedal assembly, there are ECM calibration steps that need to be performed for both the APP and the TP any time they're unplugged. They're in the FSM section EC - Engine Controls under "basic service procedures".