Hello. I'm writing bc my tl is idling lower than usual, around 660 and has a low muffled sound when driving. Slight whistling when decelerating and applying the brakes. There is a small exhaust leak where the left muffler connects to the resonator pipe flange and a small rust crack in the right muffler where the pipe sticks out. I took it to an custom exhaust shop yesterday to take a look and he said it sounded like a cold air intake leak. He did not believe the exhaust was causing the problem. This has been sounding like this for about 4 months since I had my oil pan replaced. This weekend I finally had time to do some general maintenance, which was cleaning the throttle bodies and plate that covers the intake manifold. Cleaned the ports, which were not bad and cleaned my kn air filter really good. I have yet to remove the egr and clean it. I installed a Honda pcv in 2020 and am not sure if that needs replacing again. No check engine lights, no surging idle, just acceleration not as crisp as usual. Thanks

 

Morning. As a follow up, I continued working on my 02 Tl and removed the intake manifold, throttle body, iacv and egr valve for cleaning. The iacv was dirty, but not horrible. The egr port under the manifold had some carbon, but not enough to clog the flow of air. After resetting the ecu, removed ecu radio fuse, and adjusting the kn air filter in the box, the car no longer has that sort of muffled sound. Its still idling low. I'm going to either repair the exhaust or replace it asap. Going to a different exhaust shop in the am to see if the can repair the muffler and resonator pipes flanges to seal up the exhaust leak. I checked around the intake manifold carefully when the manifold was off and saw no signs of an vacuum leak. I'm apprehensive about using carb cleaner to check for a leak. The pcv may be clogged, bc there was some standing oil on top of my intake manifold. I already ordered a new Honda pcv. Will keep you posted.