Update

I made a mistake, my fuel pressure is 55psi KOEO and 48psi after 10 minutes. this is after installing a new fuel pump and fuel filter. battery voltage during the test was 12.45 volt.

I have a 2001 Blazer 4.3 four door automatic 2 wheel drive, when brought up to operating temp stalls when stopped at a light or when cruising at 45 to 65 mph. There are no codes. This has been going on for about 2 weeks now and in that time we have replaced the distributor, coil, ICM, and fuel pump. Plugs and Wires were replaced about 1 year ago. Fuel pressure key on engine off is 59 psi leaks down to about 54 psi in 10 minutes. I wish it would throw a code and for the life of me can not figure this out. When it dies there is no security light on just the battery light is on and all gauges function, when it first started if it stalled at 45 mph you could throw it in neutral , hit the key and it would fire up instantly. We did notice when it was acting up the fuel gauge was fluctuating between 1/4 and 3/4. I dont know if this is a spark issue or a fuel issue. Sometimes when it starts to die it catches itself and doesn't stall. I wanted to add that when it stalls I do not have to let it cool down it fires right back up and you continue driving. The truck always gets me where I want to go but it may stall a few times on the way there.

 

A good possibility is the infamous GM ignition switch. Millions have been recalled. Might want to check to see if yours is on the list. Since it was manufactured over 15 years ago you'll most likely be doing it yourself. Next time it does it if you quick wiggle (not turn) the key it may keep running. If that's the case it's the switch.
Not hard to do, but you need a steering wheel puller and I'm sure there is a YouTube video or 2. You'll also have to do a security re-learn. Again easy, but takes 30 minutes. No need to start hacking up the wiring to bypass the security system as some redneck will surely recommend.

 

I agree, sounds like a momentary loss of ignition voltage. If you want to catch it to be sure you can hook up a lead to the ignition V+ and have a meter in the truck to watch what it looks like when it stalls. If not then the suggestion of starting on the ignition switch is good advise. Alternatively you might be able to make it stall by wiggling the key while it's running.

That said, the fuel gauge fluctuates while it's running, stalling, or dead?

George

 

These are great replies guys, Thank you.

i watched a youtube video last night of a 2001 blazer with a no start condition, the ignition switch was bad and during the diagnosis procedure he wired 12v directly to the coil to get the truck to run. I was considering doing this as well and wanted to ask what the safest way to to wire 12v to the coil and be able to drive the vehicle around. My hopes were to drive the vehicle with the coil wired directly to 12v and have my fuel pressure gauge taped to the windshield to isolate the problem.

So my question is what is the safest way to wire 12v to the coil and still be able to drive around safely?

this is the video that i was referring to above

 

I forgot to add i have wiggled and pulled and pushed the key and could not replicate the problem. i never tried that during a stall though, i will attempt that but it happens pretty quick. yesterday at a stop sign it died with no warning. it never stalls until the truck is warmed up to operating temp, so if the truck sat all night it seems to occur 10 to 20 minutes after startup in the morning. i wish the truck would not restart because this would be so much easier to diagnose but when it stalls you just hit the key and it starts right back up again and your off.

 

Re: Ignition switch. You might try taking all of your other keys off the key ring as I have heard of the weight of the keys can affect the wear on an ignition switch. Perhaps in this case it is pulling it out of position? Just a thought and easy enough to try until you do a proper repair.

Also I once had the ignition switch go out on my 1982 Honda Prelude while driving. I had no warning. Luckily it failed when I was in a small town and not along the back roads with no houses and no/little cell service. (I live near open wheat country.) I had a friend make the 40 mile drive to pick me up and later I towed the Honda back using a dolly.

 

Update

I made a mistake, my fuel pressure key on engine off is 55 psi after 10 minutes it is 48 psi. this is after replacing the fuel pump and fuel filter the other day. battery voltage during the test was 12.45 volts.

 

based on the above fuel pressure information i feel the spider assembly is leaking and ordered the updated GM version. will arrive in 2 days and will update then.

based on captn hooks thread:
https://blazerforum.com/forum/2nd-ge...eakdown-88305/
my fuel pressure being below 55 psi after 10 minutes means i have a fuel leak. seeing as we replaced the fuel pump and filter a few days ago and have exactly the same pressures and stalling problem i will assume the leak is in the spider assembly because it would be impossible to have 2 fuel pumps that leak pressure.

 

Never say impossible, not likely, tho.

 

even i couldn't be that unlucky. lol