Now it's making sense! That coil resistance is too high. It shouldn't be too far above 1 ohm. The coil needs to be replaced. Make sure the store gives you the exact one you need; check the part number they look up and make sure the box is labeled correctly. It'd be great if the coil says "for use with external ballast" or something similar but they're often blank. Because parts can always be boxed incorrectly, you may even want to bring your multimeter to the store and test it before you leave. It sounds like you may have been sold one with an internal ballast which is incorrect for your truck.

Here are some thoughts. This will likely solve the high voltage on your coil, but I can't guarantee that the coil alone will solve your stalling issue. However, the 747 ohms on the pickup coil you measured is a little high. You really don't want to see over 700 ohms. It's hard to say how accurate the specification really is. I'd hate to see you spend the money on a new pickup coil and still have the same issue, because it's not like your reading is out of the ballpark. But I will say this. Resistance goes up with temperature; and if your return path for the pickup module is already fairly high-impedance, heat may be pushing it over the edge. It's something for you to think about.

If this were my truck and I didn't mind making trips to the parts store, I'd replace the coil first because that's for-sure out of the ballpark. It's simple math - voltage in a series circuit drops in proportion to the resistances in the path. Your coil primary winding is a higher resistance than your resistance wire (which itself is usually about 1.3 to 1.4 ohms), so the coil is taking on most of the voltage. In an ideal setup, the coil primary winding and the resistance wire are somewhat matched, so you see about 7 volts on the coil, which is half of the running voltage. See what that does, and if it still stalls, go ahead and replace the pickup module. Even if this isn't your culprit; the number you measured is high enough that it needs to be serviced in the future anyway.

 

Actually, the coil does say "For use with external resistor". I did take the resistance reading when the coil was hot however, after it wouldn't start. So that might be the reason for the high reading.

I also took the resistance reading of the wire at the same time.

I did have someone recommend getting in a new pickup coil, so I will probably do that since the numbers are almost or just out of spec.

I just though I'd mention (not sure if it has anything to do with this) that I've heard a screeching noise from near the coil, usually once the truck has been running for awhile.
I had a mechanic say that it was a vacuum leak from the EGR plate gasket?

Thanks again for the help so far, I've been able to eliminate alot of things, and I've learned alot.

 

Well there goes that theory I'd check the coil resistance cold too; because 14 volts on the coil is an issue you definitely need to solve.

That screeching noise is probably a vacuum leak, and your mechanic could very well be right. EGR spacer plates are highly subject to warping and rusting, and if they're not flat they can create a vacuum leak. You can check for a vacuum leak by letting the engine idle, and leaning out the idle mixture so that the engine just barely runs. Spray carburetor cleaner at the suspected area, and if the idle speed jumps, the place you sprayed is leaking. When you're done, set the mixture back. Try to localize the spray underneath the carburetor; don't get it around the coil or distributor cap.

 

Ok, I'll check the resistance again tomorrow. I just wish I could find a definite reason as to why I'm getting such high voltage at the coil.

 

Ok, I just checked the resistances again. I'm getting 2.2 ohms still across the coil, I tested the original coil as well and got the same reading.

I'm getting 615 ohms through the pickup coil, although I think I'm going to replace that anyways, since the resistance jumps so high when its warm.

And I'm getting 1.8 ohms through the resistance wire test.

Just wondering, do you have to remove the distributor to change the pickup coil?

 

No, the distributor can stay put.

If you look under your dash, right where all the wiring goes into the ignition switch, can you see a red or pink wire that has "do not splice" printed on it?

 

Yes, thats the resistance wire that I followed to see where it went. It meets a brown wire at a little rubber connector, then continues out to the coil. I think the brown wire leads to the ignition solenoid.

This is the wire that I mentioned that seems to get very hot.

 

Hats off to all the peeps trying to help you out !!! What a nightmare, yikes !!! I just thought I'd throw something at you. 90% of electrical problems are caused by a poor ground. I would check/clean and replace if ness. the ground wire from; block to the firewall, block to batt., gauge pod to dash. I've run into some wild azz elec issues in the past; lights work then don't work, gauges reading wild readings....sometimes, start no start issues, that were all related to a poor/bad ground.

On a second thought, have you considered a MSD ignition ?

 

Hi, yes I have checked the grounds, they've all been cleaned and everything.

My problem is getting predictable, when it wont run, and what its doing; I just can't seem to figure out what's causing it yet.

I have considered an MSD ignition, but I was trying to avoid it because of how expensive it would be.

Everybody has been great! I really appreciate everybody's help. I have the utmost respect for some of the people on here, they are so knowledgeable and so helpful, without them I'm sure alot of people would be completely lost.