Mack Etech Dead Miss

[Salpolit]

Hey everyone, I have a 2003 Mack CV713 with the E7 Etech engine. Truck has been running great until on my way back to the yard this afternoon it developed a dead miss. Zero smoke when it started misfiring. Checked the EUPs and noticed when I unhook the wires for cylinder 3 EUP there is no change. Unhooking wires for all other EUPs causes a noticeable stutter. Connected them together and it shut the engine down for a split second as it does with the other cylinders so I figure wiring is okay. Noticing the EUP was old we replaced it with a genuine Mack reman as we thought that was the issue. Checked the cam & lifter roller when replacing the EUP and looks great. Still having the same dead misfire. Tried cracking injector lines, everything looks fine where all cylinders are getting the same volume/pressure of fuel evenly. 

I'm thinking injector 3 failed, and we will test that tomorrow morning swapping cylinder 2 and 3 injectors with each other to see if the issue follows. What confuses me is we did a set of 6 reman injectors roughly 2.5 years and only 25k miles ago. Could it just be a bad injector or is there something I'm missing?

[Joey Mack]

Keep doing the tests you plan to do. Just for kicks, did you shoot the exhaust manifold with a temp gun. It does sound like you figured out the cyl. Also look at the valve bridges and roker shaft bolts. Is it making any knocking sounds. ?