Sensor could be added, but I am not sure what sort of sensor would work in an automotive environment. Do you know of any vehicles that have/use humidity sensor? I am not sure how the MAF handles this but as a guess this is a smaller factor and gets added to the error column. The O2 sensors and short term trims used to zero the error out. (?)
I would like to find details of MAF operation, looks like I need to go digging.
-Tom
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