1997 Infinity Q45, mileage 120,000, with new battery. For the past 2 months, the engine is difficult to start occasionally. Sometimes, when I turn on the ignition, it cranks but won't start. After 5 to 10 minutes of sitting with ignition off, then try it again , it will fires and start right up. Car runs great and the engine never die after start. This problem happens only occasionally. Maybe 30%. Thank you.