Yes, the ECM absolutely needs a signal from the MAF to be able to meter fuel correctly.
This is not intended as any kind of lecture, but if you do some rudimentary math you would discover that removing the MAF screens on a 173 CID engine doesn't provide any real benefit since the MAF is not really a restriction.
Your ECM should be cleared of all error codes by disconnecting the battery for about five minutes. Once it is cleared you can try running the engine again to see if the error code repeats. Until you clear the stored codes, the previous error code will remain in memory for the next 50 engine start/stop cycles.
You should verify that the MAF electrical connector is clean and tight, and seated correctly. Make sure the intake tract and ducts are sealed so there are no leaks around the MAF. If the code repeats after this, you may need a replacement MAF. I would suggest checking into the Wells/Conrad replacement, since it uses a thick-film sensor instead of the frail hot wire. There is only one "screen" in front of the sensor, and it is really a flat metal matrix instead of a round wire screen, so the restriction is very minimal. These replacements are lifetime warranteed, and are about $180.00 instead of $300.00 plus from GM or the rebuilders. For my money, and remanufactured hot-wire unit is a waste of resources.