After reading the thread most people here don't know how to use Uprev and how are AFR's work,the correction factor is between 75%-125% with 100% being on the money if the ECU moves the AFR toward the 75% it is taking away fuel and toward 125% it is adding so the reason for tuning is to get the car to run as close to 100% as possible so the ECU has full range to adjust rich or lean depending on the information it receives from all the sensors.
If the ECU is not adjusted properly let say it at a giving RPM and load it is running 125% it is maxed out and can not add anymore fuel this is why it is VERY IMPORTANT to get it to 100% so it can do it job.
You guys get the point.
