Lexus RX hybrid check engine light and poor performance

Hey there! I drive an RX hybrid too, and your symptoms sound awfully familiar. I had almost the exact same issues a while back - check engine light, sluggish acceleration, and my fuel economy tanked. It could very well be the MAP sensor. Manifold Absolute Pressure (MAP) sensors measure the pressure inside the intake manifold. The engine control unit uses this information to calculate air density and determine the engine's air mass flow rate, which then determines the required fuel for optimum combustion. If this is failing, it can cause a lot of problems. Did you try scanning for any error codes?

Thank you for your quick response! I did not scan for error codes yet. Was the MAP sensor the actual cause in your case? How was it diagnosed?

Yes, it was indeed the MAP sensor. The mechanic diagnosed it using a diagnostic scanner to read the error codes and then confirmed it with a multimeter to test the sensor's voltage output. I'd recommend getting yours checked at a trusted workshop. It's probably best to let them handle it, as vacuum leaks can be tricky to pinpoint without the right tools and experience.

Thank you again for your valuable input! I took it to a workshop, and you were right - it was indeed the MAP sensor. Repair cost was 235€. The car runs like new now.