Have a misfire problem. Misses at idle and when cruising off boost. On boost still pulls all the way to the redline.

Also when coming off the throttle when not under boost it seems to cut off and stop abruptly and launches you forward in your seat (rubbish explanation I know!)

Symptoms also are worse when the car is cold.

 

Any ideas?

Hi have you made sure all the earth leads are good and tight I had a lose battery lead car would hunt when cold stall sometimes at idel or deceleration always restarted.

Never checked actually, would be brilliant if that's all that's wrong!

Could be a vac leak or faulty O2 sensors.

 

Vac leak: Visual check, boost leak test.

O2 sensors: Unplug them, does the problem disappear?

Will give that a try when the snow disappears. In the process of making a simple smoke leak tester to see if there is a vacuum leak