they are babtch fired, two "squirt" at the same time.
sounds like you have a dead injecttor/bad wiring connection, when i first got my engine running one of the injector plugs was rooted, you could move it around and it would work or not work.
i replaced it with a plug from my spare loom, and it has worked perfectly ever scince.
i should have a few plugs and injectors lying around