02 Santa Fe V6 Ocassional Idle Stall + Shift Issues

I have an '02 Santa Fe V6 with 102K on it. Until very recently, it was running very well, never had any major issues or service. Recently had major service (details below.)
Would really be grateful for suggestions. The powertrain warranty is good for 120K miles (due to the horespower class action), so I still have time left for warranty work.
Primary Issue/Symptom:
Recently it has been stalling when idling to a stop shortly after after being shut down for several hours. It doesn't do it every time, but when it does, it almost always happens in the first 5 minutes after starting. I'll come to a red light, be idling in "D", and it will very suddenly stop. It doesn't do a "sputtering stop", it just dies. I can restart immediately without any issue, and it will generally behave the rest of the way. It has not aciviated the MIL light in all this time. (I tried to pull a stored code with a generic code reader, but nothing).
Secondary Issues/Symptoms:
Since the "repairs": Some belt (or belts) is squealing (not always, but often). In addtion the shifting at highways speeds is sometimes (though not always) rougher than usual, sometimes a "stumble" shift, other times it races a bit, then jumps into the next gear.
All of the issues are intermittant -- the idle is a once every two or three days problem, the shifting issues a bit more, although only blatantly obvious ocassionaly, most often more subtle.
History: (aplogies for length, but want to be thorough.)
As mentioned, until very recently the vehicle was performing quite well. It had regular service, though not always at the dealer. Unfortunately about two months ago I learned too late (my wife was driving at the time) that it was losing coolant, and it overheated. Long story short, the heads were sent out to be resurfaced, and at the same time, I had them go ahead and replace the timing belt and water pump, in addtion to the other major service items (tranny flush, replace filters, spark plugs, belts, etc.).
Getting the work done was a long, painful 10 day ordeal at the SF delearship. The day I was due to finally pick it up, they could not get it to spark, and they spent several hours trying to get it to start. In the end, I had to return the next day, when they reported back to me that there had been a sensor problem (unfortunately, I don't specifically remember if they mentioned the crankshaft sensor.)
When I finally got the SF back, I immediatley noticed the squealing belts. When I mentioned this, I was given "looks", and asked to wait a few minutes. Not knowing I was watching, I observed the mechanic spray the belts with lube. I remeber thinking at the time that this seemed like fixing a symptom, not a cause, but after not having the car for 10 days, after having to fight them to pay for part of my rental due to the length of repairs (they admitted to screwing up on ordering parts, and then delayed sending out the heads due to other issues, I just wanted to be done with them.)
My wife initially drove the SF afterwards, and complained to me of hesitation issues. I did notice that ocassionaly (but not regularly), when giving it "quick acceleration" from a full stop, it would indeed stumble and recover. However, it was very intermitant, and the dealer could not recreate the problem to capture on the flight recorder, nor could I recreate it for them on demand. That problem seemed to lessen after a while, but the "death on idle" situation seems to have taken it's place.
I have not yet taken the car back into the dealer officially, but I did speak with the service writer. He has already hinted that "I shouldn't expect much on a car with this milage" and poor service history. When I asked what that was supposed to mean, he said that they assumed I never changed the tranny fluid, becuase when the did they tranny flush, "even when we flushed -- it still came out dark and never went pink."
Questions:
SO, based on what I have described, any thoughts on what could be the problem? I've heard/read/gotten the general ideal the crankshaft sensor can be a delicate thing, and since it sounds like it came up at the time the heads were rebuilt, might be a likely candidate? I'm thinking it probabbly is not a fuel issue, based on the "quick" nature of the stall, and the other shift issues that come up.
My big concern is that this doesn't become a fishing trip for them-- simply swapping out parts, especially non-powertrain (non-warranted) parts. I'm not very confident in them based on my history with them, but feel like I should go back to them first, before moving on to another dealer. Thoughts again?
Many thanks in advance to all who reply,
d.
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If you're not confident in their abilities and honesty, I'd recommend moving on to another dealer first. Trustworthiness and competence are the two greatest traits a repair facility can possess.
As to what it could be, I'd suspect the crank sensor too, but it seems they may have replaced it. Look at your receipt and see what they replaced.
As for the drive belt, there's not much they could have done to cause the squealing. If they didn't replace it during the servicing, you should expect to pony up for the cost of a new one. If they did, they should be happy to replace under warranty.
As for the transmission flush, if they did it properly-- it supposedly replaces *all* the fluid-- the fluid should be red. If it isn't, you're right to expect them to correct this. The issue isn't that you had never serviced the trans, it's that they didn't completely exchange the fluid. If in fact you haven't serviced the transmission prior to now, that's not an issue anyway. The recommended maintenance interval on the transmission is 105k miles.
You should expect that for your driveability issues the dealer will need to reproduce them to diagnose and correct them. With no trouble codes or any other indication as to the type of problem causing your issue, they're left with a large sea of possibilities and little way to tell which is causing the issue.
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