[MikeS100]

The air flow meter is very sensitive so it may have been damaged with the work you were doing. If it runs better with it disconnected then it could well be the fault. If you replace it pay the extra for a genuine one, the copy ones on ebay have a history or not working from the start or failing very quickly. When I needed a new one for my V70 in November I took a chance on a second hand one as funds were tight and it's been ok since, but that's always a risk and you never know how long it will last so go for new if funds allow.