93 Suburban stall problem - woman driver - help

My 93 Suburban has over 100K miles on it. Have replaced nearly everything on it. Has been fine but yesterdayas pulled out of office garage, stalled. No problem starting backup but as soon as put into drive or applied gas, died. Finally back in stall, waited a minute, backed out and drove out of garage, died on the street. Had towed to dealer; they cant find anything wrong, drove it twice, once that evening and once this morning, still nothing; no codes showing up; not dying to them. Any suggestions on whattogetthemtocheck?

Drivabilty problems can be a pain in the you know what to find if the problem does not happen all the time.
Stalling could be caused by a billion different things.Everything from a bad ecm to a loose wire.
Sorry I cant help you with out more info about the problem

Went to pickup at dealer; got 2 blocks, car died while driving down road; took it back; will see what they come up with; interesting because no symptoms at all; just dies.