BLKGT787

I have a 2012 GT C&L intake, axle back, BBK X-pipe. Today I changed to a Steeda Cat Delete CEL started flashing but no DTC. Called AM and tried multiple tunes. During one of my test runs I pulled a DTC P0305 once but no other times. Due to the CEL and the Cat delete being way to loud I switched back to the stock cats. I still have the flashing CEL but no DTC. Pulled the neg battery term and pulled cylinder 5 plug and coil and checked with cylinder 6 plugs. They looked the same. I am going to call the dealer on Monday but does anyone have any ideas.

BLKGT787

Used a better scanner than my SCT. Shows a pending code of P0305. Going to change plugs and coils on Cyc. 5.