Sons 2005 Escape is having sporadic starter problems. My mechanic has put 3 reman and 2 new Motorcraft starters on. The car will start ok for a week or two then fail.... The solenoid seems to be the trouble, if you tap the solenoid while cranking it will engage. All signal wires, neutral safety switch, etc all check out fine.

We're running out of ideas.... any thoughts would be appreciated.