Just having got to 45,000 miles I thought it might be time to change the fuel filter.. Checking the fuel pump it appears that its the fuel return line that's filtered and not the pump output. It appears that the pump pumps the fuel up to the injectors under pressure and what isn't used is returned to the tank via the filter. So the questions is should I swap the connections on the fuel pump so the filter (I will use a new one) is on the outgoing pressure side which will offer better protection to the injectors (I do wonder if one is showing early signs of failure as it consistently runs about 1ms longer "open" than the other and the plugs both look the same. Im assuming it might be slightly blocked as has to be activated longer to keep the lambda happy. Any thoughts appreciated. Dave