We had this same issues on our Astro vans. We found that condensation build up in the distributor caps was the culprit. I think we sprayed the inside of the caps with a water disbursement such as silicone or WD-40.

Try some dielectric grease on your coil & plug wire connections.

I asked a friend who owned a repair shop for many years. He suggested you check the coil and coil wire as they become corroded where attached. He says check both ends at coil and distributor.

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Originally posted by Shifferbrains:
We had this same issues on our Astro vans. We found that condensation build up in the distributor caps was the culprit. I think we sprayed the inside of the caps with a water disbursement such as silicone or WD-40.

This is what I would do. Cheap and quick test.

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Originally posted by PakRatJR:
Yup 4.3 V6. I'm actually shopping around for the coil right now to see what it will cost lol. Looks like it might actually warm up a bit next week so hopefully I cando some testing on that and the distributor. I'm actually looking up prices on a distributor as well just in case

The module is on the coil bracket, did you check that throughly? I’d be looking at that too.

The module that bolts to the distributor housing with the external plug is the camshaft position sensor. If memory is correct the engine will run most of the time if those go bad but at reduced efficiency and will throw a check engine light.

Thanks all, I will pull the distributor cap and look at that. I do remember last time I replace it, it was green inside so moisture in their would make sense.

I haven't gotten any codes pop up that were ever related to anything ignition wise, other than the occasional cylinder misfire, which was due to a intake manifold leak. But that has been repaired and haven't had any codes since.

quote:

Originally posted by PakRatJR:
Thanks all, I will pull the distributor cap and look at that. I do remember last time I replace it, it was green inside so moisture in their would make sense.

Yeah, green crusties means corrosion and corrosion means moisture/water. Not good for electrical/electronic/ignition parts.

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2001 GMC Sonoma

FF to 2:30 point and watch.

I'm guessing as other have that it is condensation and a bad wire....

Back when I worked as a service grunt I had a Jeep that came in running poorly and the customer said it always did that when it was raining. Don't know why but on a hunch I decided to turn out the lights in the service bay. That revealed a very pretty halo of blue sparks all over the distributor cap. Called the customer over for a look and suggested a new cap might be the solution. Hie reply was "bet your right". New cap and that jeep was running smooth as silk.

I would suggest that you turn the lights out in your garage and have someone crank your engine while you watch the distributor.

The first time I started noticing the issue, I did find out the cap was actually cracked. I replaced it along with the rotor and wires.

The problem seemed to have been fixed but after.... maybe a year-ish???... it started acting up again. I replaced the cap again and that's when I noticed the green inside. It has been maybe around the year-ish mark again now, and Monday was the first time it did it after the current cap.

If it is the cap itself that is the constant issue, I'm wondering what else might be going on now that keeps doing it. A cap should last more than a year I would think, at least they used to anyway lol. If it is the issue again, I'm wondering if running some grease or something around the joint would help?

I'm going with what a lot of people already stated, bad distributor cap and bad spark plug wires. Unless last time you paid for a good set, the less expensive parts do crack and let moisture in. Also as some have stated dielectric grease at the wire terminals is a good idea.

Way back in the 1970s I had a Honda Civic that would crap out in heavy rain. It was the ignition coil. Spraying the coil with WD-40 would get it going again. Replaced the coil and problem was fixed.

To get a longer life for your distributor cap you might replace the PCV valve. One of the ways for humid blow-by to escape is along the distributor shaft, and into the distributor cap.

After that, when it's humid outside, the compromised cap will let you down.

is there some kind of shield/cover that is missing that would allow rain water to enter from above and hit the cap on a regular basis.

Is the cap sealing tight to the distributor, is there a gasket between the two that is needed/missing,

When you replace it, use dielectric grease on all the terminal ends of the coil and plug wires, if you do replace it, buy a GM part this time, some of the aftermarket crap on Amazon are fakes, AC plugs and coils are heavily faked, you can't always trust Amazon sellers.

Quality plug wires, OEM cap, OEM coil,

Good luck

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2001 is too new for me, even my previous 1998 was too new.

Then you'll have to accept that you'll be dealing with bugs and problems. Always a trade off.

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Originally posted by jimb888:
Bizarre, electrical issues are the worst. I'm stumped.

Regarding: "I had a similar issue with a 2002 suburban.
Under just the right conditions (hot/cold delta, humidity, etc) it would do the “crank but no start” thing if it had less than 3/8 tank of fuel.
Apparently it is a “known” issue as I found a reference to it online.
Sure enough, next time it happened, I just poured a few gallons of fuel in it from one of my lawnmower cans and it busted right off."

Curious, did you ever find out what was happening ?

This is bizzare! My 2015 V6 Accord does the same thing. I just fill it up when it's at a half tank.

Seem to remember some S10's had an issue with fuse box corrosion, also check the + wire that feeds the underhood fusebox for corrosion.

Well..... Thanks all for the suggestions so far.

I was able to get out and play with things over lunch today. Went through a full 32oz spray bottle with water, spraying anything and everything I could get at. Distributor, wires, coil, any and all connectors and wires and whatnot, around the intake manifold and the intake for the throttle body, and no joy with anything.

No sparking, arking, spitting, sputtering, hiccuping or even the slightest hint of any kind of issues. I did look at the fuse box and didn't see any issues there, but I wasn't really able to get the best look underneath, but what I could see looked ok. I even hosed around that and the computer, and even sprayed directly into the alternator just for shits, that didn't even do anything lol.

Oh well, back to square one for now more or less I guess.

I had a 80 F150 that did this. Horrible performance on a humid wet day.

The distributor caps were so tightly fitted it would draw condensation and the water collected on the underside of the cap shorting out the spark. I finally caught it during a warm April day on the way to work, wiped it out, sprayed it with WD40 and all was good. It tried again a few months later.

The solution is to drill a very small hole in the cap or distributor body to allow venting. Once I did that it permanently stopped. Next vehicle I had was a 90 Jeep Cherokee and behold! the cap came with a vent on it! They understood the issue and proactively fixed it.

Drill a small hole in the side and done.