back fire

hello sir can you help me how i can tune my car with back fire when i release the pedal on my GM motors, how i can optomise ignition at which degree

on a gm ecu you can disable dfco by raising the enable temperature , and you can lower the timing in the overrun area,

how much timing the lower the more aggressive, my car backfire with just 20 degree especially when the exhaust is hot, you might want to go lower