My Lexus Rx 330 drags to accelerate when the engine is cold

[Ijuo Godwin]

My Lexus Rx 330 drags at every first acceleration when the engine is cold, but never does that when hot, though it reverses normally. What do I do, kindly advice.

[RX400h]

If there are no codes/warning lights, the only thing I can think of is perhaps a stick-open thermostat. This would prevent the engine from warming up, quickly.