MAT sensor data

[John T Stein]

Thanks to all who posted responses to my recent query about software 
to retreive ECM data.  At $400 I must try to find some "deep 
pockets" to split the cost for "Diacom" with.

I am presently "tinkering" with a 2.5 liter four  in a Pontiac Fiero 
and am puzzled as to what information the ECM gleans from the air 
temperature (MAT) sensor which is mounted in the (heated) intake manifold.  It 
seems that if the ECM wanted the temperature of the ambient air the 
sensor would be placed in the air filter or other non-heated part of 
the intake.  Granted the ambient temperature could be INFERRED from 
readings from this sensor,  engine speed, and MAP but that sounds rather 'round 
about.  Is this sensor yielding other intelligence??