Depending on which coil you use, you might/might not need the ballast resistor. If your coil is If the coil resistance is 1.5 ohm or less, you need a full 12 volts. However, unless you recently replaced your coil, it wouldn't take 12 years for you to realize there's an issue with your coil or resistor. I can't find fault with the Pertronix installation instructions. 

I don't know for sure, but I would think the Pertronix would either work or not work.   When my old Igniter 2 on a Y block years ago died, it just DIED, and it didn't last me more than a few months...that was a ballast resistor issue.  Anyway, it just wouldn't spark at all.  I put the points and condenser back in and it fired right up.
My current Y has the first Igniter in it, with the resistor.  

Have you checked all the wires on the ignition system , making sure all connections are good.  Give a gentle tug on all the terminals to make sure you don't have a bad connection there.

54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

I have the petronix 1 and have the later model distributer. I have also retained the original resistor. 

You must have the 1st-generation Pertronix, if you retained the resistor. A family member has been using the 1st-gen. Pertronix in his 65 Mustang for years. As far as I know it's been trouble-free. As you probably know, you have to be careful not to leave the ignition on without the engine running. Do you have the 56 Loadomatic distributor? 

Yes, I have retained the stock resistor.

I can't say how long the Pertronix system should last but I would say after 12 years, 50,000 miles and no points or condenser to replace you did good. There is the possibility the coil is failing or there may be a bad connection from the ignition switch to the coil and distributor.  I assume the rotor and cap are good and all it tight in the distributor. Are you still running with the ballast resistor? 

64F100 57FAIRLANE500

I was hoping someone on here could tell me how long I reasonably could expect a Pertronix ignitor ignition to last. I installed one on my 56 Victoria 292 about 12 years and about 50,000 miles ago. It has been trouble free. I started it yesterday morning and let it warm up in place only to discover that it had died minutes after I walked away. It started again ok and ran until I had to stop for a light where I had to do a brake stand to keep it running. About a mile later when I arrived at my destination it stalled as I parked it. It would not fire to start again and I suspected it had jumped time as the vacuum wipers would jump a bit as I released the key. I called AAA and tried it one more time while I was waiting. It started and ran ok on the way home and ran great today in the driveway. I am afraid to drive it anywhere. The holley carb seems to be okay and I suspect the petronix. I hope someone on here knows how long these units last. George