So it turns out if there is an issue with the MAF (or you leave it unplugged ) the ECU has a function in place where it’ll operate the fuel injectors based off just RPM and TPS. There’s even an enrichment value based off coolant temp! The EVO guys call this “Alpha-N fuel tuning” and its function was a mystery for many years.
As you install larger injectors it might be wise to scale down this table in case you need to use it. Say when an innercooler pipe blows off and you have no tools to fix it…
Hell if you’re feeling daring, try fine tuning this table and drive around with no MAF for a while. The closed loop function doesn’t work with it unfortunately.