hi my dad has a 2006 mondeo 2.0 tdci 115ps ghia. the glow plug light flashes on it from time to time it runs fine but sometimes its down on power and runs rough. if he stops and restarts, everything is fine for a while and the light goes out.The car has 127,000miles on the clock and puts out heavy black smoke under hard acceleration . I have a can eobd 2 diagonstic s that I purchased of ebay . i ran a scan but not showing any faults or codes,any advice would be appreciated confused