Mazda Repair: 92 mazda b2600i, mazda b2600i, wiggle test

Question
This truck will run for a few minutes and then die.  It may or may not start after it has cooled off.  It looses all spark after you run it for a while.  The owner installed a new ignition coil and a new module in the dist.  I have done a wiggle test and heated up a few things with a heat gun but it doesnt seem to change anything.  Let me know if you have any ideas.   Thanks Dave

Answer
Wow, my first guess would have been either the coil or the module.

Get the truck warmed up so that the ignition system fails. With the truck still in "failure mode," and with test light in hand, start checking the ignition system from the spark plugs to the battery. Check for spark at the plugs(done that). Check for spark at the coil (probably already done too). Check for power to the coil (on the plus side of the coil). If there is not power to this wire, then follow it from the plus side of the coil all the way back to the battery. Ok, you'll probably find the problem before you get to the battery, but you get the idea. If you have power to the coil, then check the signal wire. A Haynes manual will tell you what to check for on this wire. Heck, Google might tell you too. Again, follow this wire all the way back to the problem.

Note: If there is a fusible link on the coil's power wire, it is possible that the fusible link is flaky. If there is a regular fuse, you will probably need to test the fuse with the light.