1985 Ford Ranger stalls, dies at stop sign

Ford CODE 18 : IDM circuit failure or SPOUT circuit grounded. The computer sends out a timing advance correction to the ICM over the SPOUT wire.
IDM - Ignition Diagnostic Monitor. Check the ECT or the IAT sensor for your problem. Also, check the SPOUT/IDM wire going to ground making sure it isn't damaged.

You mentioned the sensors below: I do not know what these are, and do not find them in my chilton's manual. can you explain more?


ECT or the IAT sensor

I would be happy to. The IAT is the Intake Air Temperature sensor and the ECT is the Engine Coolant temp sensor. Both of these sensors determine how rich or lean the air fuel mixture needs to be based on engine temp and ambient temperatures. If either one tells the computer the wrong temp, it can cause too rich / lean mixture and an engine stall.