So i decided to finally replace my rear knocc sensor today. Been dealing with the light for 2 years now and finally bought all the parts. Pulled it all apart using the thread i found on here for reference, replaced the knock sensors and torqued them to 15ft lbs, covered in silicone, and replaced the old wiring harness with new. Put everything back together using new intake gaskets and torqued the intake to spec. Started it up and it sounded fine. Closed the hood and called it good. Couple hours later i go out to get some food and the thing starts idling real rough, hesitating on acceleration and definetely misifiring. When cruising i get a flashing check engine light above 30mph and a solid check engine light other times. I run the codes and i get P0300. I assumed i screwed something up so i pop the hood, double check the sensors removed, the injector connectors are tight, and there are not any leaks in the intake. I dont have a temp gun but i did spalsh a little water on each header tube and they seem to all be smoking hot so not a total miss at least. Any help would be seriously appreciated as i'm pretty sure the install went perfect.

Truck is a 2004 2500hd 4x4 w/ 6.0L GAS