Car doesn't idle unless Mass Air Flow sensor is unpluged

Okay, so I bought a 1999 Galant es with the 2.4(4g64) engine and I had replaced the timing belt and pulleys, head gasket, replace everything in the head and got the headed fixed up and cleaned, changed the belts, fuel pump assembly, ignition wires, ignition coils, spark plugs, the oil and the coolant. Now the car starts and revs up to 2000- 2500 and dies unless you keep the revs up, but when you unplug the MAF sensor it with rev up to 1500 on start and go down and idle between 1000 and 500 for a couple mins before dying. Can anybody give me some advice on this?

try swapping out the maf, if it doesnt work then most likely its the ecu. and thats all if you did the timing correctly