i have the same problem. I have a 2009 G37x. I put a used engine, wire harness, ecu, because my old one gave out on me. After installing these parts and having the dealership reprogram my ecu to the right VIN. I started to get random check engine codes. (P0300, P0011, P0021, P0524, P2A00). I clear the codes to ensure it was just a bad relearn. But, I still keep coming up with these codes after the dealer flash my ecu. I had replace the O2 sensor, both cam sensor and actuator, the oil pressure sensor. After driving the car for at least 30 min @ 70 MPH on the highway, nothing happen to the car. After letting the G37x sit for about two hour I took it for a drive and this is what happen (It seems to occur within 50 miles of refueling and at highway speeds. Also the engine is at operating temperature. When it occurs, the engine will not run over approx 2500 rpm and if it does reach 2500 it shakes violently until back down below 2500. If you pull over and shutdown, it will restart and run fine. No error code that I can read with my cheap device. Also no CEL. The violent shaking is really violent and it feels like theres a big chain attached to the axle stopping the car from moving forward.). I don’t know what else could cause this problem. Could it be a bent fuel line or pump?; Could it also be that my catalytic converter is partially clogged and is restricted the flow of exhaust. This guy posted a video of the same problem. But now one has a answer to it. I have no more check engine codes because my car pass the NYS emissions test yesterday. 🤯😡. Someone please help. I don’t know what else to do