Still trying to track down the cause of an annoying misfire. Falters under load at low (1500) revs. Generates 29CC (misfire on cylinder 1) and 29CD (misfire on other cylinders). Following up on some suggestions from StephenVA. Have removed injectors from cylinders 1 and 2 in preparation for swapping. Noticed that the 3cm metal cylinder between the “o” ring and the tip of cylinder 1 injector is quite discoloured (black and oily looking) compared to cylinder 2 (quite shiny). Any suggestions as to what could cause this? Not sure if I am looking at a cause or an effect.