Accurate tuning depends on sampling exhaust gas from a location with consistent, concentrated flow — typically achieved by relocating the O2 sensor bung. The client has declined any modification to the exhaust system, including sensor bung relocation.

As a result, the calibration will be based on data from the exhaust manufacturer’s original sensor placement, which may not provide fully saturated or consistent exhaust gas exposure at low speeds and part-throttle conditions. This can produce less accurate sampling and, in turn, a less precise tune than would otherwise be achievable.

Any drivability symptoms that persist after the tune — such as flat spots, surging, hesitation, or inconsistent throttle response — cannot be reliably diagnosed or corrected through the calibration data alone under these conditions. Addressing such symptoms would require additional trial-and-error adjustment based on subjective feedback and observation rather than sensor data, and will be billed at the shop’s standard hourly rate.

By declining exhaust modification, the client accepts these limitations and the associated additional cost, if any, of post-tune adjustment work.