It starts 1st pop every morning but by the time i get to the top of my drive the check engine light comes on an my fans click on, an by the time i get to work which is 5mins away theyve clicked off again. if i was to turn off then start again i'll have to hold key on winding it over with my foot flat to the floor and it will roughly crank over until clears itself, with a billow of black smoke out the back an then runs and idle sweet as, and drives fine, it has no real pattern to when its goin to do it, if i stop after a small drive, then when i go to leave it will almost everytime start rough. no-ones been able to sort it, iv done most obvious things like airflow meter an sensors, any ideas?

Cars & Trucks - Subaru - Impreza - 1995 Subaru Impreza