Volkswagen: Thing Starting Problem, generator voltage regulator, electronic ignition system

Question
I have a '74 Thing.  The engine is all stock except for an electronic ignitor (empi) in a mechanical distributor.  Coil, ignitor, generator, voltage regulator, and plug wires have all been replaced within the last 6 months.  A few days ago the car wouldn't start.  The starter turns but there is no spark coming from the coil. Electricity is getting to the coil. I put in a new coil, and the car started right up.  I figured it was a defective coil, and went on my way.  

After I got home the car would not start again.  I managed to start it once after several attempts.  It idled good for a few minutes then cut out and hasn't started since.  I checked the coil again and there is no spark.  All the wires on the coil look good.

Any ideas?  What can cause the coil to go bad?  Should I replace the ignitor (perhaps I'll just use points).  

Any advice would be greatly appreciated!

Answer
Mike,

a) I am jealous you have a Thing.  It's my favorite VW.

b) Remove the ENTIRE electronic ignition system, and replace it with the stock.

It has absolutely no performance improvement on a stock engine.   They simply cause more troubles, and often create shorts.

Let me know how you make out.

Ron