Hi can anyone help, my 2.2 diesel is showing an engine management light which the mechanic says is the EGR Valve we have cleaned it that only works for about 20 miles before coming on again, then we replaced it with a second hand one this has also done the same thing, a new one has been quoted at £300 plus fitting plus vat, before I even think of doing that is there anything we are missing ? I want to really keep the car on the road as it is a great car but haven't got endless pockets