miss fire at revs

I have recently fitted a 200tdi into my lightweight but a miss fire has started to occur when I'm at relativly high revs and white/blue smoke. I have replaced one injector which seemed to improve it slightly (number 1 injecter as it seemed to be in worse condition) I have also tried running it without the turbo and the miss fire still occurs, any thoughts or advice would be a great help

Cheers !

Air in fuel can cause problems especially if all fuel lines not 100 percent.
I had a problem with my s2 tdi misfires smoke etc, changed one dodgy injector at a time, filling fuel filter with injector cleaner would sort it out for a few hundred miles then it would start again.
Have now fitted another injection pump and its totally different to drive


Lynall

Cheers for reply, I found a fuel leak/air leak comeing of the lift pump so I'll fit new pipe tomoz and see what happens

Cheers again