coil light flashing?

hi guys
I got 52 plate ford transit 2.0 diesel and for the past 3 or 4 months sumtyms i get the coil light pop up and starts flashing when tis happens i lose all accelearation i have to turn it off and restart it and its fine and the coil light goes out, but yesterday i was driving it and it cut out completely whilst travelling at 50 mph again the light came on and started flashing then i tried to restart it and it wuldnt i had to get towed hme by AA he did try and get it going and said i had diesel coming up to the injectors and if he was too squirt easy start into the air flow tube and it was to try and start then it isnt the fuel pump. Well it did try and start but didnt fully turn over he said change the fuel filter and it mite b ok, well i done tht and it still wont start please HELP ME!!!!!!!