Where is the MAP Sensor in a 1987 f150 located?

 

Ah, making the rather safe assumption that not much changed between our model years - the MAP sensor should be back in the firewall area, mounted just to the passenger side of center. There should be a vacuum line from it leading to the intake air plenum, and an electrical connection.

 

on your firewall next to the heater box it has a vacuum line goin to it