Hello
I have a 06 base TL, 127,000 miles. All stock (water pump,timing,tensioners,ect done) and I have a low sounding popping noise that happens when driving, does not matter stopping (braking) starting,very low speed,cornering (slow and fast) nothing consistant about it. I had a 4-wheel alignment done and I think that is when about the time it started (I don't drive car often). My shop could not adjust the rear because of corrosion so I ordered 4 new rear arms from Ingalls and also ordered every nut,bolt and washer from Acura.
Problem not solved so I ordered new rear sway bar links and bushings and every bolt,nut and washer for the rest of the rear arms as I felt the bolt may have been corroded and binding causing the pop. I took arms off,bushings and bolts like new. All Acura parts-did not solve.
I bought car with 3 miles on it new from local dealer and 10,000 miles later it wore the left front tire out on the inside so I put a ajustable ball joint on the upper. I just fixed it myself instead of go throught the BS at the dealership.
This noise reminds me a sheet metal popping, like flexing in and out. Or something hanging in one of the pillars and it hits against something. It has gotten louder and more frequent, the driver (my wife) say she can hear it on the outside when she has her window down to go through gate at work (stops to scan card).
I'm ready to move to the front next,sway bar links and checking the ball joints. Car has been driven very easy and washed out underneath weekly in winter time.

 

I've already addressed the shifter noise issue. The car has never been wrecked, but at 750 miles a small deer ran into the right front and car ran over it causing the steering wheel to be off from normal 12 o'clock to 2 pm. I paid a shop to align,never another issues.

 

I had a similar popping on my '04 about 6 months ago.

Look underneath the car, directly below the driver seat and passenger seat, you will see two 10 or 12 mm bolts (don't remember) that are right next to each other. Try tightening these bolts down.

I went through torquing down everything possible until these bolts and the popping noise has been gone since.

 

the 2 that are in the frame rail? At the point the front frame rail laps over the floor rail?

 

yes