F Y I :
Its called an "inertia switch", if the truck get tilted enough or if the airbags are deployed it shuts the fuel off, safety issue. All you had/have to do is like said above, its located in the pass. side kick panel, and push the reset button..........then it'll run like normal.
As to the airbag isn't replaced, you'll have a light on the dash tellin you that it's not hooked up.
I've done all this on the 96 I bought that was hit lightly in the RF, but it kicked the airbag.