Econoline stalls

[almoststupid]

I replaced the idle air control valve, thought it was fixed, but it is stalling again. When i come to a stop, and more frequently when I shift ton reverse

[Johnny Mullet]

It could be lots of things.

Tune-up including plugs and wires (depending on engine)
Dirty Throttle body.
Fuel filter or pump pressure.

What year and engine is it?

[hammrs1]

mine did the same thing. it turned out to need a tranny service. the filter drops down allittle when you stop or shift gears and loses pressure. when you give it gas it sucks the filter back into place.