[KR500]

I always like Tom's ,what I feel are well founded diagnostic habits, and one thing I have learned is Test, Don't guess. I didn't see or read anything here if the coil was heated and tested. Possible breakdown after heating would cause the symptoms you describe. I also don't like parts changes with out testing the suspected parts that may be bad. If you suspected fuel delivery problems install a small auxiliary gas tank(quart or half gallon ) and go test drive. Heat can do funny things as far as resistance in circuits as well. Good Luck and DON'T walk away from a challenge!