2022 Y62 Patrol Running Rich After Headers And Cat Deletes

[davethe]

Hello all,
Looking for some help for a customers y62 i've tuned. I've read the car with PCMflash and modified it in Winols and runs fine with no codes, but after 100kms of driving/3 ignition cycles, it runs really rich (can smell it bad) and consumption goes up aswell as losing responsiveness. Any ideas and has anyone had this before? I've got a read from the car with HPtuners and cant see anything that i could change to fix.
Cheers