CEL and Traction Control light - P0171
 

So I recently just installed an aftermarket over pipe and UEL headers and didn’t have any issues at first, however after about a day or two the CEL and TCS light came on and I am unable to turn off the TCS light. I also installed a CAI but put the stock intake back thinking it might have been that. My LTFT percentage is way too high at 37% when idle but goes down to normal percentage range when driving. Could this be from an exhaust leak/vacuum leak? It’s a 2017 auto.

Are you absolutely sure there are no exhaust leaks from the header or overpipe install? Or the intake fiddling? If not, was the car tuned for the headers & overpipe?

high probability of exhaust leak near the front o2 sensor
stock tune with stock airbox won t give +35% or more of ltft just for exhaust header unless the front lambda is measuring some fresh air

I’m sure I tightened everything well but there might be an exhaust leak. I’ll have to check it out to be sure but I used an OFT2 stage 2 plus tune for the headers. It’s only high when idling but when driving the percentages are normal.