hi there i done an engine change on me s2 and the engine was running fine when i took it out the other car now its in mine there is a miss fire when u rev up its gone and when u are driveing slow it there and when u pick up speed its gone the only thing i have not changed is the metering unit cud this be the problem and as my sump gasget is leaking somone said it might be that cud some help me plz

 

Yeah if the sump is leaking badly enough that will cause an air leak you will idle really badly. Also if you have not swapped metering heads over the fuelling will be wrong so get it setup asap mate.

 

have you checked the spark on the misfiring cylinder, ht leads, plugs, spark from coil?

 

hi there i think me turbo might be buggered i changed the meetring unit and its idleing fine now and i drove it about and the missfire went and then when i put me foot down and it boosted up and come back i think its over boosting as well anyone know wot it wud be cheers

 

what turbo have you got on it? Is there blue smoke coming out the exhaust, as that is a sign the turbo is knackered.

 

yea its just a normal t3 turbo yea there is blue smoke its pumping a bit of oil out and there is play in the shaft but wud it cause the missfire to come and go

 

well im not sure about the missfire but airleaks will cause a misfire as Karlos said... if there is play and oil then your turbo is definately leaking. There should be a tiny bit of play but not a lot at all.
I would change the turbo as it will need doing anyways, then take it from there. One thing at a time is always best otherwise it starts to get overwhelming.