It is actual cylinder #4- second one back on the driver's side.
Do an injector buzz test to make sure the electrical connection is good to the injector and that the solenoid is ok. Any electrical issue should have thrown a corresponding electrical code, but always a good place to start. Next, I would pull the glow plugs and do a compression test and a leak down test if any of the values are out of range. If that is ok, then check for bent / broken pushrods. If everything mechanical is ok, then I would either send the injector out to be tested or swap it with it's neighbor and see if the code follows the injector. If the code moves with the injector - you know what to do.
Do an injector buzz test to make sure the electrical connection is good to the injector and that the solenoid is ok. Any electrical issue should have thrown a corresponding electrical code, but always a good place to start. Next, I would pull the glow plugs and do a compression test and a leak down test if any of the values are out of range. If that is ok, then check for bent / broken pushrods. If everything mechanical is ok, then I would either send the injector out to be tested or swap it with it's neighbor and see if the code follows the injector. If the code moves with the injector - you know what to do.
