Chrysler Repair: 1988 New Yorker 4 door 3.0 spark loss

Question
Hi,  This car will start and run fine for about 15 minutes at the most and then it just dies.  After which it has no spark at the plugs or at the coil itself.  The coil can be made to spark once by disconnecting the ground wire.  Pretty sure the coil is not the issue, but I have no idea how to proceed.  The following morning it will start right up and run again for 5 to 15 minutes, then the problem is the same all over again--no spark.  Thanks Tom

Answer
Hi Tom,
Try to get a fault code readout using the ignition key: "on-off-on-off-on and leave on" doing that in 5 seconds or less elapsed time. Then watch the check engine light remains "on" to see it begin to flash, pause, flash, etc. Count the number of flashes before each pause. Then repeat the process to be sure of an accurate set of flash counts. Tell me the counts in the order of appeance and we'll go from there.
Roland