Hello Pete, I agree with the others about not having the correct equipment to do thejob, but understand you trying to fix it by guessing at the most likely part, but I would at least test the suspected part with an oscilloscope or whatever was required, to confirm it faulty though. That said, a possible cause of your fault may be the fuel rail pressure sensor. There is a tsb for the connector wiring overlay and sensor.But as already said , without being able to get a fault description, then it would only be guessing & you could end up fitting many new parts & the customer returning again & again. Hope this helps, Regards,Andrew