I just got my new RX400h last month and I drove it very gentle. In last two weeks, time to time I heard a big hitting noise from the engine compartment. Now I can reproduce the noise. Whenever I accelerated the car, then very quickly to press the brake, I can hear this noise. Sometimes very loud, feel like something hit my car from the ground. I also have a rattling noise in my car from rear door area.
I drove my car to dealer to fix this noise. I reproduced the noise to the dealer technician and they said they didn't see that before. Now it has been 3 days and they still can not isolate where the noise coming from, neither the rear rattling noise. My service rep told me they will have a specialist to diagnose the problem tomorrow.
Is that a serious problem?