renphilia

Hey everyone, I'm a new member here. I just got my RX300 for 2 weeks and now whenever I stop on traffic lights/trapped in traffic jams, the idle is rough although the RPM is okay (about 600-750). Sometimes it may go to 530-550 based on my visual observation of the RPM gauge. And it happens only on 'D', which is really rough and the vibration can be felt inside (the passenger's seat vibrates quite hard, I'd say as I could see it moving), on 'N' and 'P', the vibration is minimized although I feel that it's not yet normal. Been 2 days since this occured to the car. And it's currently quite heavy for the car to run fast
I'd say that maybe the throttle body needs to be cleaned, not sure about the IACV but I think it's still good enough as I haven't experienced any stall yet on the engine. It still runs and good. I've seen a lot DIYs here but now I just want to make sure what is the first I need to do ? clean the throttle ? the MAF ? or maybe the mountings ? previously, the CEL is already ON with code "system too lean" and "airflow sensor", but I still could drive it as usual bcause I thought it was due to the CNG (oh yeah car has CNG installed with it), on petrol/gasoline there isn't any CEL indicator

p.s hope to exceed 400k miles with this RX. (car is now 145k miles) <- although i personally think it's been tampered. not the original mileage.

salimshah

Welcome to Club Lexus.

We have very few members who have CNG as alternative fuel. I would suggest discuss the issue with local experts.

Just make sure the CEL is working ... it should light up when you move the key from ACC-> run.

Since the vehicle is new to you, you may like to have the OBDII codes read, There may be a pending code which can go away or turning into real fault.

Salim