First time this happened, after driving only about 2 minutes, I got to the store, and a few minutes later went back out to my Blazer, and started it, it started up, then instantly stalled out. I tried it again, it started up, then stalled out instantly. On the third try, it started fine, didn't stall out, but when I put it into reverse to back out of the parking space and it almost stalled out when I put it into reverse, but then the idle came back up to normal. It was then fine the rest of the way home. It runs fine, and did not stall out again.
When I got home, I turned it off, and started it a few times and putting it into gear and it is fine. I did notice a few days ago the clock on the Delco radio has been randomly resetting itself to 12:00 when the car is turned off. It only did that randomly, but it reset itself today when I started it and it stalled out. If that has anything to do with it.
Is there anything I should look for to see what this might be?
The check engine light is not on, and I did a scan with a OBDII scanner and it shows everything is fine. About 2 years ago I changed the spark plugs, wires, cap, and rotor.

 

Off the top of my head I would say you have a ground problem, start with battery terminals and work back. The main body ground is probably Ok if theres no problem cranking but the only way to know is clean it. Next would be the chassis ground, smaller black wire off negative battery terminal.
Search around and see if you can find a ground distribution wiring diagram for your truck and clean them all up.
Come back with how that woks out then if need be we can get deeper.

 

Ok, thanks. I will look into the battery terminal wires like you mentioned. Is the main body ground the wire from the firewall to the engine?
I was thinking maybe a bad ignition coil or Throttle position sensor?
I will try to find a wiring diagram too. thanks!

 

Don't think it's the coil or the TPS. The real good clue that your "lucky" to have is the radio loosing it's time. That's a real good sign of a bad connection. Sometimes you won't even have that and with no codes it will make you goofy. There is one ground back on the firewall on mine and one up front over in between the battery and radiator, I think.

Go over to the BF homepage and in the google box put in "Ignition switch". See if anything applies to what's going on with you.

 

I checked google for the ignition switch, but everything I find says their Blazer stalls out while driving or doesnt start at all. Mine randomly stalls out instantly when I first start the engine, and only when it does that, the clock resets itself.
I will check the ground connections and see if it fixes it. I did notice when I removed both battery cables that the negative cable had corrosion on the underside that contacts the battery terminal. The positive cable was fine.

 

Alright, I just cleaned all of the corrosion off of the negative battery cable, everything else was fine. When I reconnected the cables, I started it, and it started, I revved it, an it stalled out. I started it again, and it was fine after that. I even tried turning it off and restarting it a few times and it was fine every time.
Any ideas on my next step to check out? I am lost. Thank you very much.

EDIT: starting about 2 weeks before this stalling out problem started, I did notice a few times the clock was resetting itself randomly when I would start the truck, but the truck would not stall out.

 

If anyone else, my wiring knowledge is for sh-t.

 

Peel back the boots on both battery cable connections and check for corrosion. Then check the pos connection at the starter; the neg connecion to the engine/frame, make sure these are both clean and tight.