While the dealer was pulling up car after failed diagnosis, the car threw misfire for cyl 2 and 4 codes. I never saw these codes. Dealer says replace coil pack, plugs and wires with OEM. ( All good brands, under 20k old, plugs were already OEM).
Picked up car after they replaced parts.Dealer says issue is fixed for the most part, just hesitates a little while going down the road. Issue came back within 500ft out of the parking lot. (I knew this would happen). Dealer work order shows mileage in and mileage out at the same reading, so they didn't even test drive it after their $450 "fix" before telling me everythign was alright.
Service advisor takes my car for a test drive after I came back, and it did to him what I had brought it in for, after assuring me it was better.
On my receipt for the coil/plugs/wires Dealer states front 02 sensor reading wrong, causing bad fuel trim, and rear o2 reading 0v. Dealer states they will not check into this issue because of my UEL headers. I ask why they replaced the other stuff without testing it just because it wasn't OEM, when they had a test saying something else was wrong. Again, dealer states they will not check into this issue because of my UEL headers, won't even try to fix it unless I get OEM headers and axleback back on the car.
After a long discussion with the service advisor and his manager I got a full refund. I then walked to parts counter and bought OEM upstream O2 sensor, replaced it on the side of the street a block down the road, and everything is fixed.
Annoyingly the O2 sensor I took out was an identical bosch unit as what the counter guy gave me, but this one works for now at least.