Well, its mega down on power and has an intermittent misfire above 4k.

I have two suspicions (because the ignition side of things is fine).....the first - the cat has been rattling for quiet some time, so it could be the cat has finally sh*t itself and has a blockage in the exhaust system.

Or, the MAF sensor is dead. I tried unplugging it and its exactly the same, no difference with it plugged in or unplugged, starts and runs, ok low down and just driving slowly, anything more than half throttle and its all over, just doesnt go.

Any thoughts/experiences with the zetec cat/MAF?

Cheers