I am new to this forum but have been searching for an answer to my issue and have tried all suggestions and come up empty. I have just purchased this car from a mate and know the service history of the vehicle. It has however developed a weird knocking noise at the back of the engine close to the high pressure pump. This noise is not always present and once it starts if you turn the ignition off and then start the vehicle again it will go away for a while then come back. We have used the launch x-431 and the mitsubishi evoscan software to check codes and watch the RPM/Timing advance. When the car first starts it idles perfect at around 750-850rpm and the timing sitting around 5 will stay like that for about 2 or 3 minutes then when the knocking starts the rpm drops to between 550-680rpm and the timing advances to around 16. If at this point you turn the ignition off and restart the car, the noise will go away again for a few minutes before returning. We cleared the error codes when got the car and there are no new error codes. What is weird tho is that if you just ever so gently touch the accelerator and just get the rpm back up the noise goes away. What is also weird is that if you turn the Air Con on the noise almost doubles. The car drives fine however is a little gutless when the knocking is going on. Have changed oil and oil filter etc, have changed plugs, put new fuel in tank and still the noise happens. After going thru forums and threads we thought since it seems fuel related we removed the first microfilter temporarily to see if the knock went away. Have ordered replacements. I have recorded a video of the noise, it may not be clear to hear until I turn the AC on. Have also attached an image from the Evoscan software which shows the change in RPM/Timing. We were also told to check the fly wheel to torque converter bolts which are all tight. When under the car the noise is definitely higher more towards mid engine.
[BBvideo 425,350]http://www.youtube.com/watch?v=Z692iu2GKnI[/BBvideo]