ignition switch or lock cylinder or ?

[she8iff]

Noticed recently my truck would stay running without the key in it. One day the key just fell out and no problem , engine kept running. Today I went to start up , all dash lights came on , radio played , but truck wouldn't start. Anti-theft light not doing anything unusual. After trying to start for a while tried unhooking negative battery cable for 5 mins. No start. Kept trying. it finally caught. drove to my destination and back without shutting it down , got home , turned it off. It will not start. Ignition switch? Lock cylinder?. What is it's problem?

 

[mountaineer3]

I have 03 Mountaineer that doesn't have as bad problem as you do. It takes a few seconds{sometimes] for the starter to engage after turning key to start position. Wondering if this is a sign of switch or starter or starter relay going bad. no codes, would appreciate some advice on this situation