Lesson should be...if you get a CEL after doing something. Go back over what you messed up.
If it ran fine before you fixed something, and now run's crappy, go back and unfix what you screwed up.
Basic lesson most of us learned at a young age.
174,000+ miles, 5/20/12 new ej257 short block, 8/20/11 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. Also CHECK YOUR OIL, these cars use it.