I have the 2006 5.4 triton 3v. It seems to be running on 6 cylinders and very rough. It is very difficult to drive, it is running so rough

It is not firing on cyl 2 and 6. I have disconnected the coils on these 2 cyls and it has made no change to the running of the truck, this is how I know the cyl that are not firing. I have swapped the coils with proper firing cyl and the missing did not follow. I have also swapped the plugs and it has not followed. I pulled the coil and plug and with the engine runnning I can see the plug firing. I have put a meter on the injectors and they are all the same. Number 2 injector makes a loud knocking sound that dissapears when it is disconnected.

I am going to swap injectors with ones from a good firing cyl to see if the issue follows.

The truck has 310k kilometers (193k miles) on it. I have replaced the cam phasers, vct solonoids, and the imrc.

My question basically is, what are the odds of 2 injectors going south at about the same time and is it worth trying the swap or should I just replace them.

 

Its possible but you'll have to swap them to be sure

 

I swapped around injectors and the problem did not follow. I pull the left valve cover to see if maybe a valve was stuck open and it does not look that way. I am going to do a compression test next. (would have done one first but my compression tester wont work on this engine).

Is it possible that there may be some sort of blockage in the intake? If my voltage to the injectors is not high enough would that possibley cause this issue?

Any help would be appreciated.