fanchius

My Rx300 2W 2001 model has 149,000 miles on. I recently found clicking noise came out when I release gas pedal at speed of 10 mph up to 30 mph yet the noise is short -- I push pedal and then totally release, then push pedal again in the said range. The metal-like noise sounds coming under the gear shift box. I am not sure whether the recent fuel mileage drop by 5% - 7% because of this problem. It did not come out every time I released pedal, but then, it became more frequent after some 800 miles. Incidentally, fuel mileage drop appeared first, and noise happened about 2,000 miles later. Anyone had the same experience and solved the problem? Would appreciate any recommendation.

Lexmex

You may have to have someone listen from outside the vehicle.

I had a click that would occur when I lived in Mexico and it turned out it was due to a bad gasket on a joint just in front of the catalytic converter.



Just to the right of the converter and it is held in by two 14mm bolts, gasket was so rotted out.

fanchius

Thanks Lexmex. I don't have an idea how someone can follow the car and listen from outside while I am driving in that range of mph. Could you tell me the specific gasket location of what you pointed out? Could it be possible that I can visibly check it underneath? I google search such symptoms, and it rarely comes out with the same topic and solutions. In our community, there were posts on Lexus SC400-- see the link below:
https://www.clublexus.com/forums/sc-...l?ref=esp-link

In the posts, someone mentioned bad control arm bushing, and another said Flex Coupler, which is an expensive part.

Another link suggested a bad exhaust-manifold gasket -- see the link below:
http://wiki.answers.com/Q/What_does_..._the_gas_pedal

imherenow

ok i had similar problem too (well kinda) but there wasnt any reduction in fuel mileage. try making a video of it

https://www.clublexus.com/forums/es3...p-in-guys.html
mine was heat shield problem. and is now fixed

Lexmex

It might be possible just to tighten the two 14 mm bolts holding it to see if that helps it improve assuming you hear a click here.

At higher speeds, I let my fiance drive the RX300 and I drive her 4Runner and listen. However, this issue might be heard at lower speeds because often certain sounds are audible from the outside at say 5 mph that might not be audible until 10 or 15 (even minor popping). This exhaust gasket one is something that would be school zone speeds even in a parking lot or just down an isolated street enough to see if it is coming from underneath the vehicle or closer to the brakes (that's the two places here I hear clicks.

If that gasket is rotted out, that seal might not be tight and there is a lack of back pressure that point in the exhaust. Something similar occurred with loss of power when I had the flex pipe crack underneath the engine and my uncle welded the thing shut (third photo), but I later had the pipe just replaced as part of an exhaust modification.

One minor possibility and this happened to me recently is that the lug nut bolts weren't tight enough on one of my wheels and I heard a clicking noise, but again that would be heard near the brake area.

Any suspension bushing can usually be noticed by jacking up the vehicle (going wheel by wheel) and shaking the wheel and see if there is any play usually in the area shown in the fourth photo. I usually don't get a click with that one, but a wobble in the wheel.