sir,i too have a mits diesel van...pcalibrate ko nung nakita itong symptoms na to:

1. too much black smoke/soot on the tailpipe..
2.magaspang/mahina na ang hatak...and
3.makonsumo..

pag nagpacalibrate ka for the diesel engine,katumbas yan ng pa-tune-up naman for gasoline engines..

most likely,fail ka sa emission test and be a good contributor to global warming..

pag nagpacalibrate ka suggest ko din na check mo din fuel filter mo..mahal na crudo ngayon and takaw huli panaman mga engines natin..