thanks for the reply, When i unplug the MAF the engine just dies out.
I used a code reader at My dads friends garage. I have also had it on one of those cheapy bluetooth readers off ebay. Would a air leak around the intake manifold cause issues like this? only i get what i would describe as a hissing noise coming from that area when i turn the engine off. it seems to happen at any RPM but mainly lower down but have had it at 4000rpm but then it doesn't happen all the time, maybe once or twice a week.

Thanks

Ben