Our Rover 'V' reg 200 diesel car started to stutter occasionally soon after a new fuel tank was replaced at a local garage. It usually jerked twice within a mile from home then might only do it once on the way to work which is 18 miles away. Revved up car in neutral & saw black smoke (sometimes) from tail end if that's any help. Mid-week it lost power on the dual carriageway and was taken back to the garage by recovery truck for inspection. They told me car started first time and ran ok on the road. It was then left on idle for an hour and didn't stall. The garage said they fed diesel into the injectors, an auto electrician put a computer on the car and said there's absolutely no fault at all evident to diagnose problem. We are told it could be a faulty fuel injector pump (but not guaranteed to be) which is £about £800 for the part alone. We're told we should continue running it incase it clears up and couldn't be any clearer than that. Just wondering if anyone can shed some light on this?? Just wondering if it could be dirty fuel, or a dirty fuel filter? I'm grateful for any advice.