My mk3 mondeo diesel (130)starts and ticks over perfect,but when driven normally misfires after approx 1500rpm.I took it to a friendly garage for diagnosis, they told me no faults showing up,and advised before taking it back to them to change diesel fuel filter and add some wynnes system cleaner to diesel tank,this I have done and after 150miles still misfiring.I have noticed that if I floor the accelerator when changing gear and keep it floored when in top gear NO misfire,so at the moment I am travellind in the highest gear possible,and when my speed is too fast,foot completely off pedal,then to speed up foot on the floor,if I try to cruise misfires,will appreciate any advice before going back to garage Thanks

Hi it's most probably a split egr to intercooler pipe just a small split in it can cause your car to run badly.

Thanks for tip on hose will check this w/e