I have a 2005 Vauxhall Combi 1.3 cdti model van, it misfires on idle & smokes slightly when pulling away. The misfire clears when it reaches 1500 rpm. Had new timing chain fitted, new EGR valve, been plugged into diagostics. There are no faults showing. Still has misfire on low revs when cold. Can anyone help please.

Tony, May 2011