Ford: 92 f 150 4.9, solenoid starter, starter solenoid

Question
on a 92 truck you can start engine turns over find and will start as long as you have key in the crank position you let off to the run or on position it dies has new solenoid new switch  even changed pcm but still have found problem any help would be very helpfull and appreciated

Answer
Hello


You have replaced the solenoid (Starter mounted) and the switch. Which switch?  the firewall mounted one (used to be called a firewall mounted starter solenoid) or the ignition switch?

Are any codes being generated?

Will it stay running if the throttle is held slightly open?