Yo,
Your 94 5.0 has the MAP sensor.
Mounted on firewall, passenger side as shown circled in blue,
Overview; "...On gasoline engines, the manifold absolute pressure (MAP) sensor senses atmospheric pressure to produce an electrical signal. The frequency of this signal varies with intake manifold pressure. The powertrain control module monitors this signal to determine altitude. The PCM then adjusts the E4OD shift schedule and EPC pressure for altitude. Symptoms: Firm shift feel, late shifts at altitude. Possible Diagnostic Trouble Codes: 126-129.
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More info in my site @
http://schwimserver5.com/index.php?index=138
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Your 94 is a Speed density EFI that uses a Manifold Absolute Pressure Sensor (MAP), a Throttle Position Sensor (TPS), an Air Intake Temperature Sender (ACT) that gives the engine certain volumetric efficiencies over it's RPM range. Speed density EFI also uses what is called bank fire injection. 4 injectors are fired at one time on each side of the engine (only 2 wires for firing injectors from EEC-IV).
Mass Air Electronic Fuel Injection (EFI), aka Sequential Electronic Fuel Injection (SEFI) is in 95 5.8 California models and in all 96s. Mass Air directly reads the mass of air (or number of molecules of air). By doing this, it can detect the changes in the volume of air, in addition to it's pressure & temperature. Mass air has one separate wire for each injector & fires them twice for every power stroke of the engine. This makes the injector timing more accurate & will help emissions along with power.
GL
Al