1993 Chevy Blazer Engine stalls, won't start, starts after

I have a 1993 Chevy Full Size Blazer, 5.7L TBI Injection. My vehicle while driving ( no regular pattern). Vehicle stalls, driving along starts to cut out, trying to accelerate produces nothing, won't idle and finally dies. Vehicle will restart but again produces no RPM under accelaration and dies when engine goes to idle. On 4 previous times was able to let engine sit for 10 minutes and engine would restart and run fine. Recenntly, engine died and would, t restart even after 1 hour, had towed to shop and after 3 hours on mechinics third try engine started and ran fine. Each time problen occurs can be weeks apart but seems to be getting worst. Mechinic cannot pin point problems and says without it happening he can only guess.
Can you help please?