I have an 06 1500 with the 5.7 in it. Last week I had replaced the lifters as well as the head gaskets and all the gaskets in the valve cover. I checked the heads, checked the cylinder walls and heads, made sure it was all clean and in good condition. I put the engine back together and started it up to test drive it and out of no where my 4th cylinder starts to misfire. I took out the spark plugs and checked them they were good, the sparks plugs are getting fuel as well. Then I checked the coil and the coil is still good. Then shortly after starting it up to see if anything changed it started showing me the same code for cylinder 4 misfire as well as fuel injector circuit code for cylinder 6. I'm not sure what's wrong with it. Any ideas?