Hi alo was driving the z today and gave it a boost boost cut out and so did the car restarted the car starts straight away but its realy lumpy revs yo up and down like it wants to cut out but dont and when i pull off its judders and black smoke comes out realy rich smell of feul definatly missfiring any ideas?

I would say its possibly your maf mate, try unplugging it and see what happens.

Check all the pipework under the bonnet.

Specifically boost pipes.

Cheers guys il check them now

I bet one of the big four next to the fan has popped off.

Sounds like it might be a boost leak, the way that the boost dropped off sharply then would run after a restart. Because at idle it would kind of run, the black fuel smelling smoke would support this as air leaking after the MAF would not reach the engine and it would overfuel.

Edited September 6, 201411 yr by tomfromthenorth

Intercooler pipes are favorite for doing this.

 

Jeff TT

Cheers for your help guys it was one of the intercooler pipes had slipped off was perished abit luckily I had a new set off silicone ones so I'm back to boosting cheers guys

Good to hear.