7.3 shuts of w hard restart, help!

[debsart4941]

My 2002 7.3 has great power and runs great until it STOPS! It usually happens when I take my foot of the pedal or stop at a stop light. When the engine retards from being under power to idle it'll shot off suddenly and without warning. It's hard to restart often requiring me to move the water separator lever behind the fuel filter, or at times it must sit and wait for about twenty minutes.
I can smell a strong odor of diesel but I see no apparent leak. The engine does not smoke excessively.
In the beginning it did this mostly when the vehicle was under 1/4th tank of fuel but now it's doing it even when I have a full tank of diesel.
I check the oil and fluids, and have changed the filters and breather without luck. I put the Excursion on a computer at a local parts store with no luck, it showed nothing wrong.
If you've experienced this I would greatly appreciate your help!
Thank you, D

[SuperCrutyPS]

A couple of questions.

Has the CPS (Cam Position Sensor) been replaced? You can do it yourself, or check with Ford - Some were done under recall.

You say you smell diesel. Is this before you ever opened the water separator? I ask because if it is before you ever opened the valve, the o-rings in the valve could be bad. I replaced the whole valve assembly, but an o-ring kit is available for it. If after you opened the valve, the tube the runs down from the valve only goes down so far and sometimes draining diesel will hit steering components that are below the tube.

Just some suggestions.

[debsart4941]

The diesel odor is all the time, not just when I've moved the water separator lever. I noticed the odor some time before the engine began shutting off and continues now. It may not have anything to do with this problem.

Thank you