Notice engine giving me this weird symptom like battery is dying while sitting. So I'll go start it after not driving for 3 days, the starter sounds very weak like it's not getting good juice. But then let's say it starts, it will only stay running if I give it a little gas and keep my foot on it. If I let up the van dies instantly. There's a point where after so long of giving it gas to keep it running, it will idle just fine, start back up and idle just fine too. This only happens when I leave it sit for 3 or so days. Bad battery? Parasitic draw? After running, the starter sounds strong again. Which leads me to believe it's a power issue. Like the alternator isn't charging. Which recently had this weird episode where the volt guage and temp guage would flicker every 7 seconds. That went away but it's been acting weird since. Possible bad alternator?

 

How old is the battery? A weak battery can cause all sorts of interesting issues.

 

Sounds similar to when I have the battery unhooked for a while and the ecu has to learn in order to keep things running.