Kalaw

2007 Chevy Tahoe. I am getting a stability track off and my motor has a very rough idle. Low engine power. I had changed my spark plugs on Saturday and the truck ran smooth until thursday eveing then stability track off came flashing. Went to get reading code and said misfire on 6 and abs . I changed out 6 and it has oil gunk on it. Put a fresh plug in but not change. Still idle rough and stability track off keeps flashing. I then pulled all the other plugs and they looked fine, only six had the sludge on it.
Please Help somebody