GM-GMC: chevy truck, engine parameters, chevy truck

Question
i have a 1997 chevy half ton 5.0,at,ac,basic package.quite oftenin the past 3 weeks it suddenly stops running after idling for a bit. it needs to cool down for about 15 minutes or so before it starts again. we had fuel pump replaced. and a full tuneup done. no trouble codes show up on computer analysis. getting very expensive and frustrating!!! please help!!!

Answer
For what you are describing the stall condition is heat related.  If I were to diagnose this condition I would be sending you home with a device called a flight recorder, it records a predetermined set of engine parameters when a button is pressed.  When the button is pressed it records a snap shot of the 30seconds before and the 30 seconds after.  It can be a very very helpful tool when diagnosing intermittent problems.  A second way to go about diagnosing it would be to wait unitl it stalls and won't restart and start checking the basics.  Do you have spark, do you have fuel pressure etc etc.  That will atleast begin to narrow your search.  Unfortunately intermittent concerns are the most difficult and generally most expensive to find.  If the shop you have been dealing with has tried without being successful I think if you explain to them that they have cost you $$$$ without fixing the problem they should treat you properly (no charge until they find the problem, then discuss a reasonable price)
Hope this helps