my guess, based on prior cars without cats, is youre seeing the AFR become quickly very pig rich as the throttle closes and revs drop, and some of that fuel igniting late causing some smoke out the exhaust. i had one car that would actually shoot a small flame doing that exact same thing.
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2010 Nissan 370Z 40th Anniversary Edition #762/1000 | Forgestar | Michelin | Swift | TRS | Z Speed | ARK | Z1 | Hawk | CFE | Evo-R | GTMat | Stillen | Seibon | Whiteline | Pioneer |
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