A friend of mine has a '98 1.6 16v Vectra and after a few years of trouble free motoring it has suddenly started to play up. It started after filling it with petrol and then finding it very reluctant to rev up at all - you could press the accelerator to the floor and the thing would just splutter/idle unless you pressed it down very slowly and then the revs would eventually pick up. I changed the fuel filter on it which seemed to help a small bit, now when you press the pedal to the floor the revs go up, just very slowly (doesn't splutter at all). I checked the fault codes and it's throwing out 1405 - EGR valve. Do the above symptoms sound about right for a faulty EGR valve? Is there any way of servicing/cleaning this?