Cranks but no start.

So I got another 5vz-fe question, on the spark plugs and fuel pressure. Fuel pressure goes up to 45psi while cranking and when I stop cranking it drops to 10psi in about 10 to 15 seconds. The plugs , #2 & 4# are clean and wet. #6,#1,#3 and #5 look like they are trying to fire "I am getting a popping noise" I'm wondering about the injectors or fuel pressure regulator. More the injectors. Truck has approximately 130k miles, timing is perfect plus tried a different ECU