Ford Repair: Bronco-84 ignition, inline fuse, switch system

Question
My Bronco-84 351 2bbl,starts right up and when I have the key in start pos. but when I let the key back in running pos. it stops.I have checked just about everything from ign.switch to ign. module so now I suspect the PCM.I have only been able to retrieve one code from it and it says the MAP sensor is bad,so I changed it and it is still the same so I would appreciate any suggestions before I buy a new PCM which I´m not even sure is faulty.Thank you

Answer
If the inline fuse at the solenoid is in tact,you need to look at the ignition switch system.I know that you said that you checked from the ignition switch,but that is where the problem lies.One thing to look at might be the actuator itself.It could be defective.