A couple months ago my maf started doing the usual symptoms of failing. I unplugged it and the car improved massively. Left it until yesterday to get another, but went to eurocarparts splashed out the 80 quid and gave them my old one for a new bosch. I instaled led it and straight away it was idling high, then the weak acceleration and hesitation came back etc. is it possible I have a dodgy one? It is brand new and bosch, from a reputable dealer not and eBay jobby. Is there anything else that could cause it? Just don't understand how with it unplugged it runs absolutely spot on, but with the new one it runs ****e.