Hey, Hoping to get some insight on my 04 f150 5.4 3valve fx4... It threw a code for cylinders 4 and 7 missfireing So I brought it to my mechanic and he said it was a fuel pump module so he changed that and I was still having the problem so me and a friend changed out my spark plugs this morning same problem! then we went to the COP's we switched a couple of them around to see if it was cop's but only cylinder 7 and cylinder 4 misfired still. so my question is what is the next step to take? is it electrical issue or do I need to look into injectors?