I've been slowly working out the bugs on this car but this nagging idle problem has popped up. The car sometimes idles rough. It seems to be worse after hard driving. Sometimes though it will do it when cold too. It sputters until it gets up to 2000 rpms and the turbo kicks in. Ther is also some grey smoke (unburnt fuel I guess) that wasn't there before. I recently cleaned out the vacuum lines going to the alda from the manifold and the shifting and highway speeds improved greatly. I also put new vacuum lines on the wastegate and EGR. That also improved highway performance. I've done a diesel purge with no appreciable results. In fact, the idle might be worse. When I first changed the fuel filter after the purge, I finally replaced the old o-rings on the filter bolt. The replacement o-rings that came with the filter seemed a little on the thin side compared to what was there before. Could that be contributing? Am I grasping at straws?

The car is running better than ever at highway speeds (anything above 2000 rpm) Shifting is smooth and power is good. It is terrible at idle and start-off though. It has actually stalled a couple of times when I've tried to pull into the road. Also it makes a put-put or chugging sound like an exhaust leak until the turbo kicks in. Any suggestions?