Losing injector pulse during cranking

[superslayer]

Hello all, I'm having an issue with my new to me truck. 2008 1500 5.7 auto 4wd. 170000 miles on it. I bought it non running with the cats cut off (of course). I'm fixing issues as I find them and I've run onto one that I'm having a heck of a time figuring out. When I try to start the truck, I lose the injector pulse. I have my noid light hooked up and it flashes brightly the first time but begins to fade with each rotation until after about 3-4 seconds, it's not lighting up at all. I replaced the crank sensor (I accidently broke the old one) as well as the spark plugs, air filter, shift cable and fuel pump. I doubt those are related, just want people to know that's all I've done. I did have to get the main key fob replaced and reprogrammed but the locksmith said that all good now. The only codes I'm pulling are the passenger side O2 sensors and the drivers side downstream sensors (which I haven't replaced yet). Noe blow fuse that I've found and no other obvious damage that I've been able to find. Battery is brand new and 850 CCA but it does seem to crank a bit slow in my opinion. Just wondering if anyone here had any ideas where to start looking? I have a manual coming but it won't be here for a few days yet.
Also fuel pressure was about 55 static and 52 cranking with the old pump and the new one isn't any better. It's about 52 static and too bouncy to really tell cranking. I'm not really up one newer dodges (carb guy) so I'm not sure if this is acceptable or not. I'd sure appreciate any help or advice you guys could give. I did a search thru here but didn't see anything so hopefully I didn't just miss it.