Ive just recently bought a escort cos, a lovely motor ive got it at a good price as it needs a little tlc! mint shell! ive sort all interior electrics! now moving to the engine..

Some times when i drive it hard in 1st then change to 2nd at 4000rpm it make this massive bang out the exhaust and i loose the power, then when i change to 3rd its fine again... and it only does this occasionally.

The the engine has been rebuilt around a year ago ish, it has been know to smoke at idle when the throttle has been bliped, i havent seen do this since ive had it but i was told it did this when i bought it, the turbo has been rebuilt too.

ive taken out the spark plugs today and noticed that 1&2 are oil fouled and 3 and 4 are lean so i'm confused! has any one any ideas why this could be, i do all work on cars my self but oftern need help to diagnose!


The engines a 400+bhp build but has only standard breather system.

cheers