The problem of the car engine P1704 Code may relate with another problem of the car engine. If there is a share that wants mending, leave it to the experts. Unless of course, you are self-assured that you can conduct all these maintenances at home. You will need moderately expensive spare equipment and tools for this though. The engine should be fixed by an expert automobile engineer who knows well how to solve the car engine problem. Do not make any mistake in the car engine keeping the car engine unfixed what may make terrible problem of the car engine.