I am try to help my neighbor with his 2001 Prerunner with the 3.4l. He is getting a CEL with P0300, P0303, P0306. He has changed the plugs which he said gave it better power, but the codes came back. New set of wires and same problem. Swapped coils and same problem. The truck runs good. On hard accelleration it accellerates good but when letting off the gas it pops a couple of times and triggers the light. He took it to the local garage and they were swamped but said they thought it was electrical and not the injectors. He is planning to take it back to they after the Holidays. Any ideas on what we could check before then? After everything he has changed it is consistantly those two codes. Please help and thanks.