I was getting a cylinder 6 misfire. I ended up replacing vacuum lines. Had to pull intake for one of them. Then i did plugs and plug wires it ran worse than it did before. Didn't throw any codes so the only thing that was left was coil pack. I took one off seen a crack so i started checking the rest they were cracked to. Now runs like a new one.Not saying anything is wrong with yours but there easy enough to check.