It will cause a large disconnect between the measured air mass and the actual cylinder load, making the system difficult to tune.
If the water + methanol is well vaporised maybe the MAF wil be ok being mounted near the engine... I haven't tried this though

Ford and GM calculate the voltage offset / dead time differently.
Ford dead time is time until the injector starts to spray.
GM offset is the offset time to the linear flow rate intercept point.

What vehicle / engine / ecu / os are you referring to?

If you look back a few posts, you'll see that Antus explains it (can't change vin etc)

1979project wrote:Well in the end my other ds1245y from element 14 turned up and worked straight away. I guess the on I got from digikey was the issue.

Email Digi-Key customer service, they will probably send you a new unit immediately for free. Can't hurt to have a spare!

Yes, however it causes the PCM to lose control of the spark (bad).
Basically, with the inbuilt dwell settings, there isn't enough time to dwell and fire the coils above the standard rev limit.

Most laser cutting places have a minimum order price around $200, so you could probably ask for 200 of your trigger wheel and pay the same amount. Now, if you did get 200 of them, you might be able to sell off the remaining 199 for $25 each to like minded individuals... Alternatively, find someone e...

They changed (at least one of) the quad driver ICs (U15 in VT, seems to be an allegro UDN2559) in the VY PCM so the fault input doesn't work the same as the earlier units.

And if we look at the OPs numbers of 22 - 24" that equates to 26.8kPa - 20kPa.
So if the engine runs nicely when you are applying a vacuum level that is close to the expected idle value for a stock motor, it sounds as if the sensor itself is ok.

Is the optical pickup infrared or visible light?
In any case you might actually need to paint the paper disc matte black to improve your noise margin. Many materials that look opaque to us may still transmit enough light to make the system borderline.