2009 5.7 hemi number 3 cylinder miss fire,have replaced spark plugs,swapped coils,new injector,pulled valve cover and checked springs,compession equal to other cylinders,replaced pcm.this driving me crazy,after it misfires so many times it quits pulsing the injector.you can shut the engine off and start it back up and injector pulse is fine until so many misfires then its pulsing injector again.thanks,sam.

Make sure with a visual check that you don't have a "Bent Pin" or "Push Out" on the electrical connections for the coils or injectors.

A bent pin is where the small metal wire connector (male pin part of electrical connection) in the coil or injector gets bent over.

A push out is where the female connector in the plug gets "pushed out" backwards away from the injector or coil.

If either one happens you don't complete the electrical circuit.

It may be either or it may not be at all, just a thought of what to look for.