New MAF arrived this morning,....'Bish, Bash, Bosh, ten minutes later it's in and keeping my fingers crossed I turned the key [size=8](with her indoors in attendance)[/size] . Lumpy Running problem "Gone". A short twelve mile blast along the Blackwater Valley relief road, confirmed the misfire was "Gone". Still can't shake the feeling that this is too good to be true if you know what I mean. The MAF is definately and aftermarket jobbie (£33 new on Ebay albeit with a 12 month warranty) , so having due regard to the conventional wisdom of avoiding pattern parts I'll keep an eye on it. Even as the eternal optimist I'm hoping for the best and planning for the worst.
Looking inside the MAF body it has the usual thermistor as per the original, but instead of 'two' platinum wires it has one wire, and in place of the second wire it has a resistor. The immediate upshot is the problems appear to be resolved.
Thanks for your advice guys, and Mr Wood it turns out your initial diagnosis was correct and youre batting average still intact, thanks mate!

Sitting at my PC whislt waiting for the part to arrive I googled
"diagnosing MAF problems video" Which I found educational. which may also be useful to other members of the forum
