Chevrolet Forum - Chevy Enthusiasts Forums - Stalling out after starting, now won't start at all

My truck conked out last week, and to date, none of the repairs we've tried have worked. I'm probably going to have it towed to my regular mechanic tomorrow, but in the meantime, any ideas you all may have would be welcomed!

Truck is a 1994 Chevy 2500, V8 5.7L, 2WD. I bought it about 1 1/2 years ago, it pretty much needed nothing and ran fine, only had about 94K miles on it. Thankfully, it's not my daily driver-- I basically only use it for pulling my horse trailer (a 2-horse gooseneck, GVWR 8,000lbs, well within what the truck can handle), since it's a complete gas hog-- it gets about 13mpg empty and 10mpg hauling two horses.

I have a regular mechanic whom I trust-- I'm friends with his wife, who's also a horse person-- as well as a neighbor who's a gearhead; my mechanic handles the big stuff and Gearhead Neighbor handles the little stuff. Truck has consistently run fine all last year... its only "quirk" is that it occasionally doesn't want to upshift from 2nd to 3rd, but if I pull over, shut off the engine, and turn it back on, it immediately resolves itself and runs fine. This has happened maybe 7x total, but it's completely inconsistent and unpredictable, so I don't see how my mechanic could do anything about it.

Last year (August), my mechanic informed me that it had an exhaust leak at the manifold, on which he tried a temporary fix and told me it might not hold longterm. I noticed the truck was getting louder over the past few weeks, so I decided last week to have the exhaust manifold issue fixed before I start using it more heavily for hauling again.

The day I decided to take it in for the exhaust problem, I started it up, let it warm up while I cleaned off the windshield (damned snow!), and about 5 minutes after I started it, the engine just up and died-- it didn't sputter and die, it just SHUT OFF, like I had turned off the switch. I tried to start it back up, but nada-- the starter engaged, but it wouldn't turn over. So I called a towing company, and while I was on hold, I tried starting it again about 10 minutes later-- it started up just fine, like nothing had happened.

My mechanic had advised to take it to an exhaust place since he didn't have the equipment to bend pipe and whatnot, so hubby dropped it off at Midas... And while on his way there, it died at a red light a few minutes after he started it up, same as before-- just shut off like a switch was turned, then started up a couple minutes later and ran fine.

I informed Midas of the stalling issue and asked them to check the TPM sensor while they were fixing the exhaust manifold gasket, since I'd heard the TPM sensor could sometimes cause various weirdness. They replaced the exhaust manifold gaskets, checked the TPM sensor (said it was fine), and they said they let it run for 15 minutes, test-drove it, etc., and there was no stalling. So I picked the truck up Thursday night and purposely drove it around, ran errands, etc., seeing if it would act up again... I probably put 60+ miles on it, turned it off and and restarted it at least 5-6x, no issues. So I thought, "yay! Problem resolved! Maybe the exhaust leak was bad enough to cause it to cut out, because now it runs fine, woohoo!"

Saturday morning, I started the truck up and backed it up to my GN to hitch up and haul out for a trail ride. After about 4-5 minutes of idling in my driveway, it stalled out again, same as before-- it just cut out and died without any warning. About 10 minutes later, I was able to get it to restart for maybe 15 seconds before it labored out and died, and that was it-- it hasn't started since.

So I asked Gearhead Neighbor to see what he thought. Gearhead Neighbor did a little troubleshooting, pulled a spark plug, determined that there's no spark going to the plugs, even though it seems that fuel is going where it's supposed to go, so he was thinking it's a problem with the ignition system, not with the fuel system. He said truck could use a complete tune-up (new plugs, wires, distributor cap, rotor), plus a new ignition module and ignition coil. He was betting on a bad ignition module as the source of the problem.

So I went out and got all the stuff (plugs, wires, ignition module, coil), and Gearhead Neighbor installed everything.

And still, no luck. No change-- truck won't start at all.

It's looking like I'm going to have to have it towed to my regular mechanic, although Gearhead Neighbor is hunkering down with the Haynes Manual as we speak; I think he's going to give it one more go tomorrow, but neither of us are feeling very confident at this point.

So-------- any ideas? Suggestions??? I'm desperately hoping it's not the fuel pump, which I know would be an upwards-of-$1k repair since it's in the fuel tank....... I really don't think it's bad gas, since it's not sputtering and dying when it stalls-- it just DIES, like the plug is pulled. It's like there's an electrical short or something.