2000 Taurus stalls, camshaft position sensor code

So months ago my 2000 Taurus began stalling. It only stalled when idle, but did it very rarely. Like it would be fine for 3 weeks, then stall 3 times in one day. I took it to a shop, they said it was a code "0340" (or so says the invoice), or camshaft position sensor. They replaced it, it ran fine for a few weeks, then began stalling again.

I then talked to a friend that said they may have put it on wrong. I found another shop, brought it there, and they guy looked at the sensor, said it was fine, then tried to find what was wrong and couldn't.

I started just ignoring it. It usually only stalls out after first starting up in the morning. If it stalled I had to fight with it to get it to start again, but if I reved the engine right after starting up, it was normally fine.

So any clues as to what is wrong? I have 2 shops and 4 friends who have no idea.

2000 Ford Taurus
101,000 miles
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First thing to check is for diagnostic codes. Many of the chain auto parts stores will do this at no charge. If there are no codes, then I'd suggest you clean the Idle Air Control (IAC) valve since that is used to control the cold idle speed as well as to compensate for various engine loads. You should also consider pulling off the Exhaust Gas Recirculation (EGR) valve and cleaning it out well. If there is a piece of carbon or debris in there that is keeping the EGR valve partially open, that can cause a stalling condition at idle.

There are other items like the Engine Coolant Temperature (ECT) sensor that could contribute as well as the Throttle Position Sensor (TPS) and Mass Air Flow (MAF) sensor.

Most of these items you can check or clean if you have some patience, a reasonable number of tools, and some mechanical ability.

If your car has the Duratech 24V V6, you may also have a situation where the secondary intake runner butterflies are stuck open. I'm not sure if on the 2000 model year these are vacuum or electric controlled.

-Rod