@Ralsmith - Firstly I am assuming you will have a map that has been done to suit your header and muffler or a dyno tune.
Please first of all check your TPS and ISCV settings first - my suggestion is to set them at .64V and .76V respectively which means you will have added .04V to each above the factory setting.
What this does is basically remove the throttle lag not recognized by the ECU it's only about .5 to 1% of throttle movement but it does make a big difference to low idle tuning and decel popping.
Also once that is out the way make sure you balance each of the throttles until you are satisfied they are equal.
Take it for a test run and now see if the decel popping has improved or made it worse.
If it's stiill popping bad then try my fix below.
With decel popping you will firstly need to look at your F&L switching point to be sure which table L or F is being utilized at closed throttle - some tuners turn off the throttle switch completely.
If you have your switching point set above 0% then you will need to look at the L map under closed throttle (0% throttle).
You will notice the first column is full of Zero's - fill them all with values about 60% on the column next door.
Take it for a ride but take note at what RPM it is popping - mine for example only very occasionally popps at 1800 under closed throttle - now where else so the range I would aim for is +/- 200 RPM.
You must add or subtract values (higher numbers hPa will add more fuel) to the column that corresponds to the rpm range where it starts and continues popping Try 5% each time and test.
Adding fuel may make it worse - you might try more and find its worse then start going back to your starting point and go down.
Just make sure you have saved a copy of your original map in case you screw up.
Good luck.
John