check engine light came on started flashing. Went and ran codes says cylinder one missfire replaced all coil packs and plugs no change unpluged each cylinder one at a time to identify what cylinder is the problem cylinder 4 is where the missfire is i replaced the injector to day still no change checked with multimeter have just over 11v at injector i checked voltage on the coil pack as well it was all so fine I'm now stuck HELP LOL do not no what else to check

 

Can you compression test the cylinder.?

 

Yes will do first thing in the morning what is acceptable compression anything over 120 right

 

Try moving the sparkplug/coilpack/injector to either cylinders 2 or 6. See if the problems moves with the change.

It's possible your replacement parts are bad. Happened to me once with a set of new injectors. One was bad upon arrival.

Which plugs are you running?
OEM coilpacks or aftermarket?

 

Try replacing crankshaft position sensor which control the cylinder firing sequence and precisely tells them when to fire. I had a cylinder code that went away thank to a new oem Nissan crankshaft sensor.

 

You've stated that you've tested for voltage at the coil pack and at the injector.

Have you pulled the suspect coil pack, boot and plug as a unit to see if there's actually spark?

You're coil pack(s) may be new and in good shape but the boot and internal spring may have broken or failed.

 

Wizard and Turbobink have the right suggestions.

I would remove the coil, then stuff a spare spark plug in it. Then I would touch the bottom electrode to the engine. Have someone crank the car. You should see sparks. If you dont, you have a bad coil.