I'm not sure if I understand your answer. If you take off the air filter and block the intake opening running to the throttle body, the engine should die completely and nearly immediately. This is because the air filter should be the only place air is entering the engine.Removing the filter and covering, or removing the entire CAI and covering the TB does the exact thing. Can limit the air flow until car dies down to idle lower.
If the idle drops down to a normal idle level after blocking the intake then you have an air leak somewhere. If you take off the intake, cover up the throttle body, and it stays running, then the leak is after the throttle body and probably in the intake manifold or possibly the injector seals.