Hello all, when I was heading home from CO, I started getting quite a racket just out of Billings, MT. I pulled over and took a look and listen then I checked the balance rates on my CTS, first picture is at idle in park and second picture is at idle in drive. I put the oil cap on the fill neck upside down and there wasn't any blow by. At that time there wasn't any smoke from the exhaust. When I was driving it onto a trailer to haul home the exhaust became smoky and smelled of fuel. How should I proceed? I assume I send injectors in for testing, do I send all or just the 2? Are there any other possible issues that would cause this? The injectors have just under 60k miles, I run additive religiously and I'm surprised I'm having issues already.