I changed out my intake manifold because my old one cracked so it went well. It starts and idles fine but has a misfire under load. When I drove it seems like it got better but it's not good. I suspected a fuel injector because I have no cel and when I pulled the rail, my number 4 injector popped all the way out and I had to reset it. Now what I've done was unplug each injector and saw that number 4 is the only one that has no change when unplugged. So could it just be o rings? It doesn't leak fuel. And no coolant in the plug wells.