[Oe1979]

I bought a 2006 Titan it had a p2138 app I changed the pedal n throttle body after that I got a p2138 throttle/pedal positioning sensor switch d/e voltage correlation, took it to diferent mechanics checked the wiring all was good took it to the dealer told me the computer was bad I replaced it , now they say the engine harness needs to b replace I also get p0300 random misfires,p0420 I wonder if is all related