It cranks but does not start some times, sometimes it goes on for 10-20 secs, then next 1-2 tries it will start. Then replaced the Crankshaft sensor underneath and for 2 months it was very quick to start no problem at all, ysterday it did this no start crank several times during the day , but not today. What can it be the Cranksshaft sensor is new, the Camshaft sensors look OK. BAttery is new. Any ideas for diagnostics?