Hmmm, I wonders. Have you checked your distributor cap and the air intake system? It just might be that enough moisture is condensing in the air intake system. With too much moisture, the car would be very hard to start. That would evaporate after approx 8 mins, which would allow the car to start again.Also, how long has it been since you've replaced the spark plugs? Depending on the quality, those should be changed every 90K or so.