1998 Chevy Tahoe Starting Problem

1998 Chevy Tahoe "sometimes" will not start. Plenty of juice and cranking power. Always fires right up first thing int he morning, and if it has been sitting for a while. However, if you start and stop it several times over a period of a couple of hours (stop at store, bank, post office, etc) and the last such stop is for a short period (a few minutes, up to about 30 or so) then more often than not on about the 4th or 5th such stop it will NOT restart. It sounds like it just is getting no fuel at all when that happens. If you then literally let it sit for 5 full minutes, it will usually start BUT it (A) has a strong, distinct sort of odor (somewhat like you would have experienced in the old days ater restarted a flooded engine), and (B) will not smoothly idle (you have to keep the throttle down a bit to keep it from dying out). However, if it last for a minute or so, then it runs fine until the problem happens again. Any idea what the heck this could be caused by?



Optional Information:
1998 Chevrolet Tahoe V8

p.S. I have taken it to my mechanic twice for other issues and had him search for this while there, but he has not been able to find anything. It does not ping any problem!