I have a V90 3.0 -98 that is slow on accelerating othervise it runs fine. I have tried to disconnect the MAF while running and didn't notice any difference at idle.
The 0-60 time (11,5 sec) is the same with and without MAF connected.

The flow at idle seems okey at 14 kg/h. At full throttle the maximum flow i get registered is 408 kg/h. Shouldn't it reach higher numbers? I also think it is very flat/stable at 408 kg/h, shouldn't it change a bit at least.
In the graph below is a full throttle run, the dip is when changing gear, after the dip its about 4000 rpm to 6000 rpm.


Anyone had a MAF that was working at lower flows but was maxed out/defective before it should at higher flows?

 

Well, I just swap the MAFS with a good known one. There is no good way to test and as much as I envy your expertise with measuring things, I have never heard of a successful attempt. Still, "same with MAFS connected as with it disconnected", that doesn't seem right...

 

I changed it to a new one, still getting the same curve with max 408 kg/h (bad data reader maybe) but 0-60 mph improved to 10,8 sec.

so it made a different at least 😊