Hi I have a Defender Td5 Xreg 2001 which has for some time had an intermittent fault which results in loss of power and some surging, after some discussion on here a time ago and the Landy being sat up for a while as I have been away I am now on the case again, I have got a guy with a fault reader to have a look and what comes up is first an air something message and then when you boot it you get a loss of power and a turbo over boost fault comes up, we have cleared it and done it a few times the same happens?

So where do I start? is this a mass air flow sensor problem or something more along the turbo lines? I have tried changing the mass air flow sensor but it was not a new one so I can not confirm if that is OK, I have cleaned the filter box and all intake hose and cleaned both air flow sensors but still it happens, the guy with the reader is no Landy expert and suggested another go on here to see if anyone in the Landy world has an idea.