Vacuum and PCM

[SirKnightTG]

How does the PCM on the 3v know what the vacuum is? Apparently there is no MAP sensor on the 3v so what reads the vacuum then?

I've been looking through the Ford Service Manuals online but have not seen anything that jumps out at me.

 

[hammeron]

not 100% sure, but the PCM could know
vacuum or boost, by taking fuel pressure
at the rail and subtracting 39.


i'm curious what the real answer is, though.