Kissvalp

I have a similar problems on My xtype 2.0 diesel, on tick over the car revs slightly on its own then settles down, and feels lumpy when driving, on acceleration, lot's of embarrassing black smoke, I had a Carbon clean service done on Monday which has helped, I've switched to vpower fuel, the EGR valve looks brand new ( I only bought the car last week, and noticed that it failed it's MOT on excessive ommisions, i assume that was put on to gets pass), it just feels like there's too much fuel, I've also noticed that the MPG has dropped to 38, on steady driving, I've bought a blanking plate , a silicon hose to fit next week, but any other suggestions would be appreciated