Stalls after warming up...

[brian]

I was wondering if anyone had any idea why my Blazer would randomly stall. It will drive until it is fully warmed up (choke pops off, full power, all guages stable) then suddenly die. Doesn't matter if it's parked or driving or in any particular gear. Then, after it cools down for about 15 minutes it will drive for another 5 minutes before it dies again. The engine is stock and I didn't make any changes before this started happening.
My feeling is that the problem is either a heat short or vapor lock. However, I have checked all the wiring and it seems fine. Also, I drove over the mountains into the desert last week and the truck ran like a top. No vapor lock going up 5000 feet. I would think that the climb in 80 degree heat would vapor lock it.
Any other directions/suggestions would be greatly appreciated.

Thanks,
Brian
'72 K5 350/TH350

 

[k5blazerus]

do you have a electric choke, and have you looked at the points in the distributor.
k5blazerus

IF its not broke , break it and upgrade it.

 

[JungleBoy]

A bad coil sometimes will break down when hot, as well...

 

[71RestoRod]

Could be trash in your gas tank. I've chased similar problems a couple of times, going through all the systems, only to find out that there was rust scale or other stuff in the tank. It collects around the pickup screen when the fuel pump is running, and then clears out after sitting for a while.

Check your distributor lead too. If it is the original, the insulation might be cracked off just inside the housing. This was the case with mine many years ago and it behaved the same way (appeared to be heat related). It wasn't obvious because the wire appeared to be fine from the distributor to the coil. The right combination of heat and moisture would shut down the engine like a grounded anti-theft switch.