My 2001 1.7 DTi Van has developed a strange fault.
Drive on the motorway at 70mph and it does not miss a beat. Drive at 90mph+ on a private test track and its fine for about 10 miles then it will loose power for a second or two then pick up with a puff of soot out of the exhaust and the engine spanner light comes on. Slow down to say 70mph and its fine. Could it be a fuel problem? Just been serviced with air and fuel filters. I do about 800 motorway miles a week. Its now done 153000 miles.
Has anyone got any ideas?
Thanks In Advance