don't see any mention of what engine has the problem eightfan .... nor any mention of the time it'll run or at what speed? will it sit still and idle all day? is it well warmed up before the "couple miles"? "couple miles" means what? do you check any thing when it dies or just fidget for 20-30 minutes and try again? when it does restart, does it fire right up or require a period of cranking?
more likely fuel than ignition, maybe a temperature caused problem, maybe crud from the tank plugging the line [have a fuel filter?], or just a bad fuel pump - when it quits, immediately check for fuel in the carb [accelerator pump] as well as spark
Bill
