I have a 97 Oldsmobile Bravada, same as a Blazer, with a strange stalling/idle issue. The truck starts and idles fine if its cold and it starts and idles fine if its fully warmed up. If you let it sit for a bit so that it cools off, like at the gas station, it will idle real rough for about 5 seconds. This was just an annoyance until today when it stalled out three times in a row. I finally put it in neutral and gave it gas to keep it running. Even after I got it running it was still idling low. I drove it home which was only about 2 miles and by that point it idled fine and started right back up after I turned it off.

Another issue that may or may not be related. When I leave work I coast down a short hill and at the same spot each time the engine drops to about 500 rpm and almost stalls. I find this really puzzling since if the truck is in gear it shouldn't drop rpm's like that even if the engine completely stalls. This shouldn't be a transmission problem because I had the transmission rebuilt about 15K miles ago.

Thanks for any help

 

Have you taken a look at your MAF lately, make sure it is clean. Mine did something somewhat similar, but when I would come out from a gas station (as you mentioned) would be a dog on take off.

Would be the first place I looked!