I have a 04 GP GT, if I hit the key probably 6 out of 10 times it'll turn over, start then stumbles and stall immediatly.....what would cause this? no codes thrown. It had po455 large evap leak, the dealer replaced the vent valve and gas cap under warranty.....and the fuel filter, none of which fixed this???? And the car from 1-2 gear will sort of surge or jerk sometimes but only under light throttle...?? any ideas? It has 94k miles, I'mn gonna do the filter and fluid...maybe thats all it is?