Swoop is right one plug would not stop this truck from running l would ask you if you leave the spark plug in but disconnect the plug wire so no spark is going to that plug will the truck run. If so then l would say you have so kind of spark problem.l myself had a problem not what you are having but a problem on the same model truck approx a year ago the truck would only get spark if l disconnected the est side of the ignition module l was thinking it was a bad module but it turned out to be a ground problem Toyota had ground problem on some of these trucks you could try hooking a extra ground from the neg of the battery to the engine block and see if it starts