Wow, never heard that one before, but since it happens on demand you probably should start by determining if it is fuel or spark, probably spark, which would be much harder to figure out. Get it to the point where it will not fire, pull a plug wire, have someone hold a screw driver right by the metal part of the plug wire (make sure to wear a rubber glove) and turn it over. If it sparks then it probably is fuel, if not, well good god, could be anything electrical

If you do get spark I would bet fuel delivery, pump issue (most likely) or vapor lock in the fuel line.