Excusion intermittently stallingwhile driving

Hi everyone!
I have a 2004 Excuirsion XLT gas engine. No problems until few weeks ago when it just stalled suddenly in an intersection and again couple days ago on the highway. Took it to our mechanic who said nothing showed up as error codes when hooked up to his computer. Anyone have any suggestions? Very frustrating and dangerous also to be driving 70mph on the highway when the engine sudden just shuts off for no reason! Thanks for any advice!

Hope your \\"engine stalling or cutting off\\" problem has been solved ...
As noone replied with answer i will post my experience:
August 2011 my 2000 4x4 V10 with 204,000 miles sudenly started cutting off at idle - stoplight(s).
After restart engine required shift to neutral with foot pedal reving to keep from shutting off each stoplight so i drove directly to trusted mechanic.
Engine acted same way for mechanic who could find no computer engine faults and confirmed fuel pressure to be within spec. Then, while performing inspection of air intake delivery system discovered \\"intake hose feeding IAC valve loose as the rubber hose was deteriorated due to age, heat, and oil contamination\\".
Replaced PCV Valve & Intake Hose to IAC Valve and no repeat problem last 5 years and 40,000 miles.
Hope this helps,
Lee