Q&A

 Master

Spark plugs will not be the cause of your stalling issue.

Think sticking idle air control valve possibly. Think vacuum leak or some other reason air could get into the engine without being metered. That would be less likely, however, as it would cause a lean running condition which would give you a check engine light and P0171 / P0174 codes. This is common on your 4.0L V6, as the o ring gaskets for the intake manifold tend to leak.

Check your base fuel pressure and bleed down pressure.

Do your diagnosis steps prior to throwing any parts at it. One of the things I mentioned will be the problem.

 Master

I don't think sparkplugs or a tune up is going to help. I think there may be a problem in your throttle body area, that there's carbon built up and not allowing enough air through when it's cold and needs the ilde speed up a bit. If your vehicle has Idle Air Control (IAC), it's not unusual for the IAC valve to develop carbon accumulation which will cause stalling cold. A Ford specialist could help you.
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