Lexus IS300 engine runs but lacks throttle response and is stuck in low gear after motor and transmission swap on Lexus IS300

Some owners of vehicles that have undergone a motor and transmission swap report experiencing throttle response issues and being stuck in low gear. These throttle response problems may stem from the engine's ECU, where repinning the engine portion after programming could be a potential solution. Additionally, owners are advised to ensure that the engine is receiving adequate spark, fuel, and compression for optimal operation. Those experiencing being stuck in low gear often find it is related to transmission compatibility issues, particularly with the hybrid transmission used in the swap, which requires careful integration of components such as the bellhousing, oil pump, and torque converter. Furthermore, verifying that the harness and ECU are correctly installed is crucial, as improper installation can lead to performance issues. Systematically addressing these concerns is important for diagnosing and resolving the throttle response and gear-related problems following the swap.