Go to that site I posted and look your chassis up for code info.
The FP reg [ fuel pressure] has a vac hose On it..pull the hose and see if any fuel is evident in hose or FP port..if yes , replace it.
And lok for vac leaks.

Unmetered fuel OR intake air will screw up the adaptation and the Maf can not correct for it cuz it is unmetered. So, you thi9nk that the maf is bad, but that may bot be the case if you have a vac leak or FP reg is leaking fuel into the intake...and since those two are very common on 104 HFM systems and take 5 min to check, that is what I would do of I were you.

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A Dalton