Dano582

Hi, I am new to the forum and need some advice. I have a 2010 Grand Cherokee Laredo 3.7. I bought this Jeep from a guy that said it had gotten hot and needed a motor. When I got it home I found water pump was bad and that it had dropped a valve seat, no cracks in pistons, cylinder walls or block. I purchased a good used head and installed new seals on both heads. While I had it apart I also replaced all timing components and gears. The issue is when I started the truck up it started fine but was running very rough and showed a P0300 Multiple Misfire code also had a blinking CEL. Long story short, I rechecked timing, checked compression (125-130) all cylinders, replaced all intake and throttle body gaskets and checked for vacuum leaks. The truck still runs rough and has blinking CEL. Waiting on new coils, plugs and injectors. My question is there something I am missing that could cause this issue?