At night pop the hood and take a look, look for little blue flashes.

Take your dist cap off and look everything over, I had a screw work it's way out on my 03 and my truck still started and ran fine, but I had no power, under the hood I would get snapping noises and at night I got little blue sparks from the coil wire.

The dist cap was replaced about 20k before that and I used a nice set, so I was not even thinking that was the issue, when I took it apart I had tons of damage to the inside of my cap and the rotor was toase, I could not believe It still ran as well as it did.

Also with the cap off, grab the rotor and wiggle it around, look for side to side slop, and damage to the rotor.

 

Yeah I replaced the cap and today I replaced the rotor and tried to move it side to side and couldn't. I'm going to take my ignition coil in for testing tomorrow and get new wires. The output on the coil is quite corroded, so I guess we'll see. Has anyone tested there coils at home before? That would make life a little easier. Thanks.

 

When I had my issue I started swapping parts out, to test a coil you really need a scope, but you can check it for function by looking for a spark, but spark does not always mean a good coil.

And changing the coil out was a pain in the butt, i had to remove the rivets holding the plates together thats holding the coil, and there is a little heatsink mounted on a controller that you need to make sure you reseat correctly, luckly I work on computers so I have lots of that thermal paste, I remounted it with artic silver 5

Somewhere I have a good factory coil... I don't remember if I threw it out or not.

And while trying to figure out the problem the manager at autozone gave me a free coil wire as we both thought that was the problem, he took my old coil wire and wrote off the rest of the package.
Nice guy

 

Well I'm going to the Pick And Pull today, so hopefully I can find a whole unit. I did notice the heat sink and wasn't sure what that was for, so thanks for clearing that up. I read that if you have a multi-meter you can measure the resistance in the coils, I'm just not sure how to that. I'm also going to try and get a distributor and what ever else I can think of while I'm there. I'll post my findings later.

 

i bought the "Innova 1203 CanOBD 2&1" in April, for $220 CAN @ NAPA in town. it reads (among many other vehicles); GM passenger cars '82-'93 and some '94/'95's, and GM trucks & vans '82-'95 (1 ton capacity or less)-except diesels (i know yours isn't a diesel, but my 'Burb is, and that's half the reason i bought it). it works fine, used it a few times

had that happen twice before.

the "knock" (or is it more of a loud, hard tick?) id probably the lifters (if it's coming from the rocker, that would be it). very common in these 4.3's, don't worry about it. as for the pic's you linked, that's your coil. the ICM (ignition control module) is located under your rotor, it's screwed to the base of the distributor. when you said, "I checked for spark by doing the arc method, and I got arc on 2 of them", did you only check two wires, or all six of them (very important to know)? hope you didn't ram your elbow into the inside of the fender edge (or anything else sharp) when you got zapped.

as for measuring the resistance of the coil with a multi-meter, you need to know what all the values are supposed to be (including the variance allowed). i had a book years ago that a mechanic friend gave me, but i lost it (listed everything from ICM's, coils, you name it, wish i could find another copy (lost mine)

 

Maybe this will help with the coil testing:

Make sure the ignition switch is OFF.

1. Tag and disconnect the wires from the ignition coil.
2. Using a digital ohmmeter set on the high scale, probe the ignition coil as shown in Step 1 of the accompanying illustration.
3. The reading should be infinite. If not replace the coil.
4. Using the low scale of the ohmmeter, probe the ignition coil as shown in Step 2 of the accompanying illustration. The reading should be 0.1 ohms, if not replace the coil.
5. Using the high scale of the ohmmeter, probe the ignition coil as shown in Step 3 of the accompanying illustration. The reading should be 5k-25k ohms, if not replace the coil.
6. Reconnect the wires to the ignition coil.

 

Wow, thanks a lot for all the info. Very helpful. And I did test all the wires, and only got arc from 2 of them, I can't remember which one's though. That was with the old rotor, haven't tested it since, but it still won't start. And I don't have $200 to spend on a meter right now, but I did find a guy on Kijiji who has one who is offering to come and read/wipe your computer for $20. And the sound is more of a hard tick, so I guess I won't worry about that for now. Thanks again for all the info. I'm just going to stop buy Auto Value and get the coil tested because it's on the way to the wreckers anyway. If it does turn out to be the coil, will I have to get any codes reset? I have an SES light but that's been on forever because I have an exhaust leak that's tripping an o2 sensor.

 

the coil shouldn't cause a code on it's own, but if it caused a misfire to be read, that could be in there too. have the guy come scan your truck, then wipe it clean after you've writen the codes down.

 

OK, so I got my coil tested, all is well but he wasn't able to scan the module. So I went to the scrap yard and pulled a coil out of a 96 Jimmy, and still no luck. Replaced all the spark plug wires as well. The guy with the scanner can't come by until Monday. I was thinking it's the fuel pump, but I can still hear it priming when I turn the key, and it's a fairly new pump. Should I just go to Canadian tire and buy a reader then return it? Thanks again.

 

My fuel pump was running but only had 33 psi at the engine when it needed 58-60 psi. I got a fuel pressure tester @ Harbor Freight for $10.