I can't answer this with authority because I'm not educated in the matter. However logic would tell me that the purpose of the MAF is to help ensure complete combustion of the fuel/air mixture by measuring the air volume taken into the engine and adjusting the fuel and timing accordingly. Without the MAF the air is unmetered so the engines brain can't tell what is the correct amount of fuel to inject or where it's at with timing. The result is a less than ideal burn cycle and following on from that will be less than ideal exhaust gas. I'd imagine the O2 sensors and the cat are probably not designed to cope with that and are likely to suffer as a result.

But two things.

One is that if your MAF has been bad for some time then the fuel/air and timing have been off for some time also. That being the case, I wouldn't have thought that unplugging the MAF would have a significantly detrimental effect for the while that you're waiting to install a new one.

And second, I can't imagine the replacement part will take that long for you to get ? So I'd say for a short time you shouldn't do any material damage to O2 sensors or cat.

I suspect I have a similar issue. I've been trying to track down the reason for this annoying power loss I've got between 1,000 and 2,000 RPM for some time now. Thing is that you could spend thousands replacing this and that part without solving the problem so I've been trying to learn more of the characteristics of the symptom before I go in a particular direction. My MAF is on my radar as a possible culprit ..... think I'll try disconnecting it one of these days and see what happens.

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2001 X5 4.4i