Abstract: An automotive engine acceleration judging device sets threshold levels according to engine loads and engine speeds, respectively, so as to detect that the automotive engine is under acceleration when fluctuation levels in engine load are high, i.e., beyond at least one of the threshold levels. The engine load dependent threshold level is higher than the engine speed dependent threshold level, and each threshold level is changed so as to be higher when the engine operates at higher loads than when it operates at lower loads. When the acceleration judging device decides an acceleration of the engine is present, a lockup clutch of an automatic transmission with a fluid coupling is released to unlock the fluid coupling to at least allow slippage.