Ram 1500 5.2 stalling

Ok, I'm at my wits end. And yes, I've searched high and low for a solution,
only to find that nothing has worked. Maybe some of you here can offer a
solution?

Long story. When I first got the truck, occasionally it would stall, and start
right back up. Then it got to where I would have to wait up to a half hour for
it to start again, and possibly run fine. Sometimes it would sputter just a bit.

I'm getting a crankshaft position sensor code (have from day one), so I
naturally replaced that. No change. Still get the code after clearing it, and
disconnecting the battery basically all day.

It finally got to where it would'nt be drivable with all the stalling and not
starting. So I gave in and took it to a shop. They couldn't find a problem.
Said battery was bad, and replaced it. It ran great with no problems for one
week. Then right back to day one with minor stops, and progressively
getting worse.

I've since replaced the entire distributor, plugs, wires, tps, ignition coil, pcv
valve, oil breather, air filter, fuel pump, and relays.

Now it's at a point where the colder it gets outside, the worse it acts until it's
warmed up to operating temperature. All summer long, very little problems
until now when the mornings are getting colder. I have to drive 2 footed to
keep it running when it's cold out. After being on the road for about 10
minutes, it acts fine. When I get off work, it's warm outside, and it may not
give me any trouble at all until the next morning.

Now I'm at my wit's end. I'm thinking about replacing the iac now, but not
sure if I want to keep dumping money in until I find out what it actually could
be now. Next step is to try taking it in again hoping they'll figure it out this
time.

Any ideas?? Thanks!