2010 Expedition, starting issues. Starter replaced twice, need next culprit...

[BigOleFordFan]

Does your anti-theft light in the dash flash quickly when this happens? Had an issue similar in an 07 Lincoln MKZ that I had, and the problem was the PATS (anti-theft module) in the instrument cluster was bad. It was an intermittent problem, which made it hard to figure out, but replacing that seemed to help the problem.

I would also agree to check/swap the starter relay to eliminate that possibility. And the corroded cable end seems to be a possibility as well.

The fact that it starts fine when it does start, eliminates the battery as the problem.

This is almost exactly what was happening with my 011 EL Limited....and I did have the flashing padlock PATS light, as well as a brand new battery, cables and wiring harnesses...

It took 3 months & $3k worth of diagnostics, replacing both keys, the ignition switch, the HALO sensor, removing the remote start module, and checking most of the other stuff mentioned in this thread too.....the last dealership I took it to said the "Run/Start relay" was fried, which they replaced and it starts reliably every time now for over a month...

Fingers crossed