was trying to ask have you had a load test done on the battery in your journey not just checking it with a meter, as you say hooking another car up to it by jumping it will start it makes me think the battery is going bad enough to not start under optimal conditions, run by your local parts store and ask them to do a load test on the battery and also check the charging system to see if its up to par .only takes a few minutes and most do it for free