Why does my van only start with throttle?

So, basically, i drove it 2 hours after purchasing
and it ran completely fine.



5.2 v8 motor.

95k miles



Went and had spark plugs, power steering high
pressure hose, air filter, and iac valve changed.



Now, intermittently, the van will do this thing
where it will not idle if i dont have my foot on the
gas, for some fuck all reason unplugging the
battery and charging it fixes this temporarily, ill
get maybe a 15 minute drive before it starts
acting up again.



I wanted to see if maybe the time letting it sit is
what did that and not the charge so its sat for
the last few hours til it got cold and nope, no
start without giving gas.