Engine missing/flat spot since Airbox change?

[rjdevinett]

Hi guys,
my 2007 170 tdi dsg was fitted with a k&n induction kit but my wife was complaining that she didnt like the noise. So like a good husband i decided to put the original box back on. Anyway, since that the car has now developed a problem that when driving hard at (3500rpm - 4000rpm isn) its seems to a have a flat spot, or missing if you know what i mean. I have placed new air filter in and tried cleaning maf with correct cleaner. The cleaner seemed to cure it briefly i think but it has now gone back to missing. So could this certainly mean its time for a new maf? I just find it odd that it happened as soon as i changed back to a standard box.
Also if someone could direct me to a guide to properly check my maf with vag-com (and what reading to expect) as i cant seem to find one.
Thank you.
Dev