van problem,need help

[scoooooby]

have a mark 6 ford transit,90,000 miles,never had a problem with it,uther day felt as if a needed air in tyres,then it started blowing smoke and rattleing,continued to lose power and everytime the rattle came you were getting big puffs of smoke from exhaust,then it started giveing me preignigtion,as i was nursing it home,sometimes rattle got so loun a would cut engine off,freind that was following me said ther were sparks comeing out exhaust,anyone know the problem,plenty oil and water in it.

[ake]

EGR valve, try a search