About 2 or 3 months ago my 1997 5.4L F-150 with an automatic transmission and about 200,000 miles started having ignition problems. Every once in a while when I would turn the key to start nothing would happen, the normal instrument lights would come on and I could hear the relays working in the dash etc. but the engine would not turn over. Then when I would turn the key back off and back to start and it would fire right up. It only happened once in a while so I didn't worry too much about it but over time it has gotten worse. Now it happens more frequently and I will have to turn the key on and off several times before it finally starts. Other times when I get in the truck it starts right up first try. I have replaced the ignition switch and nothing, I've tried starting it in neutral and no difference. There really is no pattern to it, sometimes it starts first try and other times it takes a few minutes of trying to get it to start. Does anyone have any ideas of what I should check next or what could be causing this?

 

Sure.
The ignition switch is not the only part of the starting circuit.
Firewall solenoid, starter and battery cables and battery intercell connectors.
At 200k the starter is likely ready to be replaced.
The brushes wear short and hang up/ lite contact on the commentator.
The starter becomes temperature and vibration sensitive.
Firewall solenoid is not that much to replace.
It's just time to go over the start system and be sure it's all in good condition or have fun with the no cranks.
Been there already.
Good luck.

 

I had the same thing with my 99 f 150. turned out to be a bad connection on the "S" wire eyelet on the starter solinoid

 

it was the starter solenoid. i bought a replacement and while i was removing the old one i could see a very small amount of corrosion on the connections. since i already bought the part i installed it and the problem is fixed. i probably could've just cleaned the terminals and fixed it but i swapped it out just to be sure.
thanks guys.

 

I have 2000 F-150 same exact thing, mine was the starter solenoid. the way I tested it was put the key in on position and shorted a screwdriver across the two post on the solenoid, truck started up. after switching solenoid the old one was rattling when I shook it.