Lexmex

For about 8 months or so I have gotten an occasional popping sound underneath my RX. It has become more noticeable over time, but every time my cousin and I would try to check while parked, in idle or slowly going back and forth at low mph, we couldn't detect it. Then the other weekend, a neighbor of mine heard it as I was pulling in and he took a turn at the while going back and forth while I looked alongside underneath with a flashlight.

This is more for future reference, but this juncture just in front of the catalytic converter had bolts that were slightly loose (gasket was ok as I checked later and exhaust shop), but the 14 mm bolts here had to be heavily tightened. My theory is that since I have replaced the piping forward of this location with straight pipe, without the previous junctures/joints, a lot of pressure is being pushed into this location.

The indications of this sound are the following:

1. When coming to a stop, a noticeable click/pop is sensed just in front of you in the engine compartment (it doesn't feel like it is coming from underneath)

and/or

2. At say a a green after a stoplight, you start to accelerate upon and you hear a click within a second after you touch the accelerator. Sometimes, but rare, the sound can be replicated when stepping on the brake and accelerator at the same time.

The exhaust shop has seen this before and also felt to that a bad gasket could also have been the cause, though it wasn't in my case.

Lexmex

Another view of this location with the joint open.

At the end of the month, I hope to replace my current resonator with a 1 in, 2 out resonator/muffler, longer than my current one. At that time, I also plan to eliminate this piece below in favor of a accordion type joint.

thomas1

Yea, Lexus must have had a reason for the flex joint, I replaced mine with the honda style mesh over the flex coupling. Muffler shop said they are better.