[GTTboost]

I have had a new rebuild its been fine while running in for the last few weeks... its still using the larger jets whilst I'm running it in... but the boost is turned right down and just been pottering around and not over revving it...(just driving normally)

So, now its done about 400 miles and when it gets hot (after a 20 mile drive) it starts to miss-fire ...the car starts to shake with the vibration even on idle it runs very lumpy and seems to get worse?

The next day it will be fine again until it gets hot when on a long drive again?

I am wondering would this be the larger jets running whilst running low boost while its running in? Will replacing the spark plugs cure the problem? I cant really understand why it only starts miss firing when it reaches around 20 miles when out driving.. will it cause any damage to the engine if you keep driving it the last few miles home with it miss firing and running rough until I fit some new plugs? if they will be the cause of this problem? I cant understand how they are fine again once its cooled down? If they were faulty wouldnt they run rough all the time?

Thanks.