The first step is to identify at what RPM and load that the popping occurs. To learn where this happens, use the PVCX as a monitoring device and visually remember at what RPM / load range the popping is audible. For example, this might occur between 5000-3000RPM, and 25-15% load.
To fix decel popping on the Bosch FI systems, the best solution is to add fuel to the mixture and increase the spark advance.
Open the DJT tune file you’ve already flashed to the vehicle in the C3 tuning application of Power Core.
To alter the fueling during this range, the injector compensation table for the front and rear cylinder can be highlighted and multiplied by a number greater than 1 as seen in the image below.
Save this tune file with the fuel changes, flash the vehicle, and head out for a test ride. If the condition has been eliminated, then your work is finished! If it still needs more tweaking, attempt adding a few more points of fuel to these tables and repeat.
If fueling alteration alone does not fix the issue, you may need to further advance the spark timing.
Ignition Timing 3 is the table to target for deceleration conditions as shown here with 3* added to the base.
Save this tune file with the spark changes, flash the vehicle, and head out for a test ride. If the condition has been eliminated, NOW your work is finished!