Codes P0308 and P219B, cylinder 8 misfiring continuously?

I posted a forum about a month ago of a ticking sound coming from my engine. I took it to my dealership, and they fixed the issue. They replaced the injectors and seals.
Everything was great! Until now.

Yesterday I started my truck, and my check engine light was blinking, and the traction control symbol popped up. My engine began to shake. You could feel the misfire from the driver's seat. As soon as you put it in gear, it shifts hard, and the light will turn solid and it will drive normal. You can tell there is a loss in power and hesitation. I scanned it with a tool, and I got the code P0308 and P219B. The first thing my buddy and I looked for was disconnected spark plug wires and we found nothing wrong. I went to the parts store to get spark plugs and they only had 4. So, we replaced the left side plugs and plan to replace the other side today. We are going to replace the wires as well. If that doesn't fix the issue. Does anyone have any recommendations?