Hello
Please can some body help i have a ford fiests 1.8 diesel. The car starts fine and idels with no problems. If i set straight of before the engine gets warm it runs fine, when the engine starts to get warm it start to struggle, more when i start driving up a hill. when its at low revs it will take a few secounds to get going then it either kicks in and goes like rocket or it starts to stall and kicks a cloud of smoke out, engine starts knocking , and you have to let of the accelerator for a few secounds rev again at really low revs and it kick back in again.If i pull up sit and wait for the engine to cool it will run fine again. I have had it at a couple of garages now and they carnt put there finger on, saying this they havent been diesel machanics. i have changed the fuel pipes and filter empted the diesel tank as i had been told that there may be water in the diesel, and i have also put a diesel injector clean through my pipes as well please could some body help me out at all. please not i have very little knowledege on cars so could you put things in simple terms if possible.

Kind regards
Ben