Re: Bad coil?
Well now you know that there is a resistance issue, and it seems like there's too much in the circuit from your battery through your ignition switch back to the coil. You can continue two ways. The first is to check point from the battery through the ignition switch for voltage drop. This is the more telling way, as you'll see the drop in voltage and not have to concern yourself with whether X is OK or too much resistance.
The other way is to use an ohmmeter to check resistance between points in the same circuit. Either way will require tracing wires. You can go either direction, from the coil back to the battery, or from the battery back to the coil. I'd go backwards from the coil. Your high resistance could be in a wire or a connection, or even the ignition switch itself. Corrosion is the main thing to look for, although there is no guarantee that is the culprit. Take a methodical approach to it and if you skip something, make sure you don't forget to come back and look at it if you don't find the problem elsewhere.
Me, I'd check the voltage coming off of the ignition switch, going to the coil, first, then split out each section to the smallest you can without piercing wires. Once you have checked that and not found it, you may have to pierce wires. If you do, have something like Liquid Electrical tape on hand to cover the piercing after you check it, because this is a great place for corrosion to start if you leave it open. You may find, as you trace wires, that there is a broken place in the wiring where corrosion has already set in. That is a prime suspect.
Resistance in wires is almost nothing for the length of runs you are dealing with. You can find specs in this on the Internet.
Chris
