I have a e350 2007 my engine cranks but would not start. Left the car for a few hours sometimes day then it would start. Drives well with no sputter, no hesitation, no backfire but sometimes when I stop it wont start for a few hours. changed the CPS senor 3time and starts right up when I do but when I drive for a while it cranks but wont start. I put the old CPS sensor back in and started right up, but same happens when I stop and turn off car. Dealer says new Fuel pump but it just does not seem like that is the problem. Any Ideas