2006 Grand Cherokee won't start. It died while pulling into a driveway. It appears to not get fuel into the cylinders. Will run well on ether for several seconds, so I have spark, air and the engine's mechanically sound. I can't find a fuel pressure test point so I can't use my gauge. I opened the fuel line in front of the tank and keyed the ignition, the pump seems to be working. The plugs are dry. How do I check the injectors? What fires them?