Hello, I'm new to forums. I've had a 03 f250 6.0 long bed for like 3 years now. Never gave me troubles. 140k miles, recently started having troubles starting. I realized the injectors were not buzzing when key on engine off. I would cycle key until i heard it, and then it would start. Started to happen more often and take a lot longer, and now it rarely wants to buzz and it doesn't start if it doesn't. It'll crank no start. I checked ficm voltages usinf scanner. When it does buzz, it'll have 48 plus volts and 11.5 for other 2 and holds there. When it doesn't buzz it gets like 40 something and drops quickly to near 0. I can link a video. In video the injectors buzzed. I cycled key again and it didn't buzz that time and then volts were not there. I have 1 new battery and other one is old but I don't see how that'll cause it, i also switched batteries around to see if thay would do anything. Ficm is also replaced with a allant remanufanufated in 2017 from before i bought it. It has 4 pins not 7 so i replaced the power supply on it and still no luck. Also forgot to mention I've only had like 1 or 2 instances where truck hesitated on highway , and the other day it died while idling which was definitely new. Usually once truck is on it had no issues which is why I'm probably going to buy a 2nd battery to see if that does anything. There were a few codes if im not mistaken ill post pics. Any help would be great, thank you.

 

Incase video isn't working as it's not for me. This is what I get when injectors buzz, and this is what they hold.

And this is when it doesn't buzz and numbers keep dropping

 

Definitely NEED to have 2 good batteries before more testing. Low battery voltage especially when cranking absolutely will take out the FICM and possibly injectors. Ensure your battery connections and grounds are perfect. Check especially the ground from battery to block and block to chassis. My advice would be to never play around with batteries on this 6.0 platform. If you have one bad battery, you change them both.