The ECU will compensate for vacuum leaks, to a point.
I had four 8mm holes in the bottom of my inlet manifold when i removed the throttle heater plate and didnt realise they were drilled right thru. The engine started, and ran like a sack of crap, but it ran. If you revved it up above about 2000rpm or so, it ran perfectly. Below there it got leaner and leaner as the proportion of air bypassing the MAF got larger and larger. It wouldnt idle on its own, but if you kept a bit of throttle on it'd sit happily enough at 1000rpm. Once warmed up you could just about manage to get it to settle to an unsteady idle, but it would often just cut out.
Thus a small leak in a vac line, or even pulling the EVAP line off completely, would not give the no-start symptoms you were experiencing.
The engine will also start and run with the AFM completely unplugged. Though it usually takes a few goes where it will fire, catch and cutout, before the ECU realises the AFM signal doesnt make sense and starts ignoring it.
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