Well - it will do, it needs that to meter the air mass being drawn into the engine, from that mass it then calculates the base fuel needed. If it made no difference at all with the MAF off, its likely the MAF.
If the MAF is voltage based (a hot-wire MAF) then you can check its output, probably be around 0.9 to 1.2 V at idle, if its anything further out than this, its likely goonered.
However - the Germans (who made all the engine electrics for the 147 - Bosch) are quite clever sorts, so I suspect the MAF is more likely a Karman-Vortex sensor, which outputs a frequency, in which case you'll need an OBD reader to see the air mass reading.
Failing that again, another possibility is the IAT (Inlet Air Temperature) sensor, this "might" be built into the MAF, again an OBD reader needed for that one - it corrects base fuelling against air temperature (as airs density changes with temperature).
And finally, the only other sensor that has a say on base fuel quantity (and its the biggest say of them all) is the ECT (Engine Coolant Temperature), once again, sad to say - its an OBD reader job.
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