Hi Fellas. I was here a few years back, but couldn't remember my info
so I re-registered. On to our problem and thanks for any info.

So my sons 99 4.3 2 wheel drive Blazer is giving us fits. It will run fine
for a short time then stall. Crank, crank, crank, not start until it cools off,
then it runs fine for a mile or two and then it will stall again.

We have changed the ignition switch out, (that was fun), to no avail.
I think I may have narrowed it down to the ignition module that is attached
to the coil bracket through searches through the forum. Before tossing more
money at it, does anyone have any thoughts to this problem. It is not a fuel
issue, but a fire or spark issue. Thanks for any insight guys.

 

Coils will do that when they get hot, or like you said ICM

 

Thank you for the reply. We really thought we had it with the new ignition switch too.
I will try the ICM 1st. Do you know of any that are better than some? We have an orilleys,
auto zone and a carquest open today. I'm willing to bet all are chineisium though.

 

if you can afford it , go with acdelco. If not midrange,

 

Unbelievable the cost of these things. Fingers crossed, the boy is replacing the
ICM as we speak...

 

good luck, let us know

 

OK, No. New coil as well. Same $hit. Just got back from pulling it home with the GMC.
We are going to pull the battery tray and see about this possible fusible link. I would
think if it was bad, it wouldn't even start if that is toast. Any ideas? Very frustrating.

 

Let it cool off in the driveway, fired right up and let it run for about 10 minutes.
It got up to almost operating temp and shut down. Crank,crank, crank...Nada.

It seems to me that there maybe a relay somewhere that is heating up and causing it to shut down.
Is there something in the distributor that may cause this problem?

 

Put a fuel pressure gauge on it. Very easy to tell when the engine dies if fuel supply is the issue, and that is what it sounds like to me. If I was you I would get that out of the way before spending any more money on trying to chase all possible electrical demons by guessing and parts replacement. That can get pretty expensive.

You can get a loaner fuel pressure gauge from local parts store that will screw onto the Schrader valve. Testing instructions are in a sticky at the top of the 2nd gen forum. I disagree with the 60psi spec for upgraded spider assemblies and feel it should be 58psi instead - but think the rest is golden.

Most importantly, will it reach 58psi with key on/engine off and do you see a drop in fuel pressure when the engine dies?

 

Ok. Let's end this thread. I hate it when people ask for help and then never
follow through with the solution after folks on a site bother to try and help.

Thanks guys for your help and suggestions. Turns out it was the crank shaft
position sensor. It took the fellow at the shop some time to figure it out as well. Seems there is a shim or spacer, gasket? That failed and after the engine heated and the part swelled, it made hard contact with the crank and shut down the fire. After it cooled, it would fire right up, then die about the time it came up to operating temp. Gotta Love these Blazers, when they are running correctly, sewing machines. When they go down, you get a WTF moment.