I have the same issue with the toyota camry. Sometimes I drove around, stop at gas station, turn off the engine, start it fine. Then drove to grocery, pick up some items, and start it again just fine. All of sudden, I have to stop at my cousin's house to drop off something, come back out and it won't start. I have to jump start the car to get it start. I check the battery, it was fully charged to 12.6 V. What can it be the issue? It must be somewhere along the electrical system.