take it out(should be two 12mm bolts or something)
put it in a plastic freezer bag. crank when cold and see if it sprays petrol into the bag.
Also i think you could check the resistance with a multimeter but i can't tell you what it should be.
I had a similar problem with my car. Thought it was the cold start injector. Turns out to be a faulty ignition relay. I knew it was electrical because the tacho would only start to hover when it was about to start. if it wouldn't start the tacho would stay dead still.