Thanks for the recap..
so you obviously managed hundreds of miles in your 'new purchase'..
so 'worn out.. sold a pup.. is unlikely
I had forgotten it was the 1.9.. thought it was 1248cc baby engine
Years ago.. I got caught out with a 1.9
The engine 'breathes' out excess pressures.. for emissions purposes this is then ducted back to the air intake and ingested
My old car had its Intercooler full of oil.. from oily vapour settling in it
You may well find some of your excess oil has followed a similar path
Anything being drawn back to the engine could smother the Sensor in the air intake..
That can really mess.up fuelling
My message.. dont give up yet
Feel free to ask more tomorrow
In the meantime
For some photographic assistance
Search MAF in the Multipla section