1998 Blazer stalling

my blazer has 60,000 miles and runs fairly good, BUT...I can be driving it then it will just shut off..no warning (dash lights flash and door locks go on and off; sometimes SEL somes on) I can start it right up, then it may be fine for a few days then does it again. I have had it to the dealer twice (once stated battery bolt loose..tightened; next changed a spark plug) when they test drive it, it works fine. I get it back and a few days later happens again. went to garage 2 more times says no codes show up and that everything is ok. got it back on a Sat..Mon happened again...afraid to drive it. What could be wrong? HELP!!!!

Clean and tighten your battery terminals.

Are you noticing any fuses blown?

Clean and tighten your battery terminals.

Are you noticing any fuses blown?

all fuses seem to be fine

I would go to autozone and get the computer scanned for that code.

Possibly a security issue? Maybe a cat issue? Aren't the possibilities for this endless? Does the SEL shut off when it is running fine? I would get it scanned as soon as you can when the SEL comes on as BLazerLT Suggested

Possibly a security issue? Maybe a cat issue? Aren't the possibilities for this endless? Does the SEL shut off when it is running fine? I would get it scanned as soon as you can when the SEL comes on as BLazerLT Suggested
The SEL does not always come on. I did bring it to the dealer when it was on, and no codes showed. It has not been on since. It hasn't shut off since 4/25. Where you mentioned security...I have a remote start installed, been in for about 1 1/2 years. could this have something to do with the problem? I did not go to autozone yet, because the light has not come on.