Injector disappears

After 3k rpm the signal disappears and gets rough. sometimes it comes back on its on while driving or sometimes it goes off on its own. signal cylinder misfire

Did it really disappear or did you just loose your trigger on the O-scope?
In the video I didn't hear any sound that sounded like an injector shutting down.
If it does shut down you will clearly hear it. The engine will start misfiring on that cylinder and run like crap

Signal drops to battery voltage and runs rough. Hard to accelerate from the stop.

Where are you measuring your pulse from?

Maybe a wire is shorting out or some connection is shaking loose from the vibration around 3k?
Maybe there is some software error in the ECU/PCM?
Maybe there is a bad Injector driver in the ECU/PCM?

I'd start by checking the pulse again right at the back of the ECU/PCM
Check between Battery + and the ECU/PCM switched ground injector pulse wire.

If that fails, maybe carefully open up the ECU/PCM and measure the same switched ground injector pulse terminal, but measure it from the inside ( this will eliminate the possibility of a bad plug on the ECU/PCM ).

If it still fails there, I think it either has to be a software problem or a circuit problem in the ECU/PCM.
The only other possibility I can think of is maybe the ECU/PCM has some input that is out of range, which is triggering this software bug (meaning that if you fix the out of range input it might fix the problem).
Should it be that way? No. That's sloppy design. But it can happen.

Maybe check all of your other input signals and see if any other signals go crazy in the same conditions that the loose your injector pulse in.

One other random idea:

Maybe check the resistance of that injector.
Maybe it is drawing too much current, overloading the injector driver and causing the ECU/PCM to shut it down to protect the driver circuit?
I don't know if that's possible, but it wouldn't take very long to check the resistance compared to the others.

Also try moving the injector to another port. See if the problem follows the injector.
It's possible that the injector has an intermediate internal short.
Maybe when / if the short occurs, the ECU/PCM is unable to ground the unrestricted 12v source voltage

If you DC amp clamp that injector, that could also tell you a lot.
How does the current wave form look compared to the others?
What does the current do right at, before and after failure?

I only saw the signal drop out during deceleration. Deceleration Fuel Cut Off is normal, on many vehicles. Does it cut out an acceleration, too?

Stop your recording, and zoom out on the buffer to see the firing repetition.

I assumed that you had a single injector signal failure with the other injectors functioning normally.
If it is the case that all the injectors are cutting out at once, then it's probably what Chad said.

which would mean that your problem is elsewhere

im measuring the signal at the ecu. the signal is there after reving and driving the signal goes to battery voltage and runs rough. when the signal comes back it runs smooth again. this is a single cylinder misfire. all other injectors work

it cuts out while driving you feels it hard to accelerate when it cuts out it becomes rough. it shows battery voltage flat line. while driving signal randomly comes back and engine becomes smooth again. I have swap the injector around and plugs coil are new. it still stays on that one cylinder at random times. the injector is under the manifold so Im getting the signal reading at the computer.

Do you have a DC amp clamp?

If you do, put the amp clamp around that injector wire ( and maybe the voltage source wire too ).
Capture a graph of that during, before and after failure.

Also I think that most of the things on my previous lists are still valid. Try as many of those as you can.

No amp clamp.

The signal wire on the working injectors show 13.80 and goes up and down .75 to .80 the non working signal wire stays at 14.25 volts .

I pulled the plug again and that misfire new plug color is golden or copper. the other cylinders are grey normal color.

Can you post some pictures and maybe O-scope readouts?

It's pretty hard to know exactly what you mean by what you have said so far.

I pulled the plug again and that misfire new plug color is golden or copper. the other cylinders are grey normal color.

What do you mean by this?
Are you talking about spark plugs.. or maybe the plug that goes to the fuel injector?
Maybe something else?

Some pictures here would be super helpful!

Ok i swapped injector and checked ohms and the ohms are all the same. The misfire did not move to the other cylinder. I pulled the spark plug of the misfired cylinder and notice the color was copperish gold orange while the other plugs were grey. I checked the injector harness under the hood and no damage at the harness.

Any progress on this one? I'd really like to know what the final cause of this is.

I pulled the spark plug of the misfired cylinder and notice the color was copperish gold orange while the other plugs were grey.

Also, a picture is worth 1000 words. There is no way based on your description that we are going to know what you are describing exactly. please post detailed pictures.

I havent had a chance to fully check it out but did some quick checks im showing p0300 code and p0306 some times p0305 but everytime it misfire it just disables the injector on that cylinder. when it misfire all the 02 sensors read lean both banks.

Interesting find.

Up till now I've been assuming that the misfires are being caused by the injector shutting down.
Maybe it's the other way around.
Maybe the injector is shutting down BECAUSE it is misfiring.

I know that it is common on a lot of vehicles for all of the injectors to shut down if the ignition system doesn't work ( in general ).
Fuel won't be delivered if there is no spark to burn it with.

I never thought about a more detailed version of that issue, but it does make sense from the EPA's point of view.

If that cylinder misfires, it will be spraying raw fuel into the exhaust stream... shutting down the injector would stop that pollution from happening.

Maybe this is what is happening?

The thing is when I check the cylinder for spark there is spark coming from the coil. but the injector was disabled after detecting a misfire but swapping coils plus injectors doesn't change with the swap. it has new intake gaskets. when things are working fine sometimes one downstream 02 was slightly slow but it was running fine for a good 30 minutes and some times its rough from the disabled injector. sometimes it fixes it self while driving. odd intermittent misfire. if its not consistent it cant be a mechanical issue.

Have you tried scoping the power and ignition signals that feed the HV coil on the misfiring cylinder?

Maybe there is an intermittant power or signal problem feeding the correct operation of the coil ( meaning that moving the coil would not change the situation ).

I would also do this check on all of the cylinders, because misfire detection codes / counters are notorious for reporting true misfires, but reporting them on the wrong cylinders.

Also, read the spark plugs. That can tell you a lot.