I have a 94 jimmy with a Vortec V6 and it starts very hard! Sometimes you have to hold the gas pedal down 1/4 way to start it. Even when it is warm. If you don't drive for a couple of days it won't start at all. I've poured gas in the intake and it still won't start. I know its a sensor thats causing the problem but which one? Any help would be appreciated.