A starter going bad can act like that too. Our 98 was going random on no-starts last month. Jump it and it would go. Tested batteries and they were okay. Swapped between Monteros and the same would happen. Alternator was new about three years ago. That left the starter. Replaced it and it's been 100% first-start for a month now.

Big Truck: 00, 3.5, Endeavor, 5-Spd drive line in hand!
Little Truck: 87, 2.6T I/C, MT, LSDs, Tonneau Top
Her Truck: 03, 3.8, 20th Anniv, 65k
Daughter's: 06 Eclipse, Keeping it Mitsu!
FSMs: MitsubishiLinks.com