nd010693

Hey guys, I am dealing with the exact same noise. It started to me after I cleaned my throttle body. I think that has to be the issue. I think what it is, is the butterfly valve inside of the throttle body bouncing back and forth against the metal. I don't know if it is because the build up of carbon prevented the noise from being so loud, or if manually moving the flap messed up it's idle position. I read online that the throttle body should not have been removed to clean it. I'm wishing I hadn't done it now.

I ordered a used TB off of eBay, but it was messed up and my car revved up really high (scary!)

I wish I had access to a new one, but for $600-$700, I think I'll put up with the noise.

Let me know if you guys messed with your TB at all before you had the noise.

nd010693

I forgot to mention why I think this is.

When you hit the gas pedal, the valve in the throttle body should open to let air into the engine. If I hit the pedal quickly, the valve should open quickly too, and it is louder when I do it.

Also, I can get it to rattle really good at a certain RPM (I think in between 1k and 2k) which tells me that the butterfly valve is opened just enough to where it can still rattle.

I am not a technician, so let me know what you guys think!

ancdmd

Hmmm I will have to look into this... thanks

nd010693

I have THE EXACT same noise. Driving me nuts. I cleaned my throttle body as well, and thought the flat inside was rattling. Took the car to Lexus to have them inspect the TB and $200 later they said "old cars like this just make noises." Pretty pissed off by that answer.

I cannot hear the noise when the car is in park, so that tells me that the throttle body probably isn't the issue. If I am going about 50 and shift into neutral and give it gas, I can really hear it happening. So that tells me that the car has to be in motion, and that it will happen in or out of gear.

I bought a used throttle body too, and my car reved up real high too. Scared the **** out of me (I wonder if it was the same one).

Does ANYONE have a fix yet? Fingers crossed.

ancdmd

I just recently changed the catalytic converters but still have the noise. More frustrated than ever with this. I can hear this noise at all speeds when the car is moving, and it's nearly constant on the highway, and loudest at very light throttle.

nd010693

Which one did you change? Aren't there 3 cats on the LS430?

This all started for me after I cleaned the MAF, throttle body, and changed the spark plugs. I read another thread that makes me think the MAF sensor has something to do with it. I got a new one from Amazon for $75. Going to put it on next week. I'm skeptical, but if that is it, I will be so happy. I'll keep you updated.

nd010693

Just realized I thought I was in a different thread when I posted the second time. Sorry for the repetiveness. I just replaced the mass air flow sensor. Noise is still there. I figured it was a long shot. Back to the drawing board.

ancdmd

And just for the record, problem solved...

https://www.clublexus.com/forums/ls4...his-noise.html

https://www.clublexus.com/forums/ls4...-loosened.html