[Kingtal0n]

0: set or verify ignition timing is correct
1. tune up filters/plugs/pcv valve/wires/rotor/cap/etc
2. boost leak test to find all leaks , compression test the engine for good measure
3. inspect wiring / check continuity to the ECU using an FSM to guide you

4. if 1-3 fail, replace the parts in question using known good USED parts from a known good donor RUNNING vehicle.

5. FWIW I've never checked a code on any car made before 2003 and diagnostically they are very simple, i.e. with respect to the maf: if there are no leaks and the sensor is good and the wiring is good all that remains is the ECU itself, regardless of whatever "codes" you see, use common sense.