2024 Acura MDX — catalyst efficiency code but car drives normally

I went back under the 2024 Acura MDX and it only happens after a heat soak, not on a cold start. Parking it somewhere I can hear it better next time.

Log the conditions before you spend. If a shop can't duplicate it on the 2024 Acura MDX, bring a video plus freeze-frame data, not just a story. Save the big job until that test fails. On “catalyst efficiency code but car drives normally,” that was the fork that mattered for me. Had a similar mess a couple years ago and that's what finally sorted it. This is the filter I use when the thread starts repeating itself. If the story changes I'll post the new data.

It did catalyst efficiency code but car drives normally twice this week, both times after sitting. No change in mileage feel. Video is ugly but it shows the hesitation.

Intermittent stuff lies if you only catch it once. Swap the cheap/easy piece first on the 2024 Acura MDX and see if the fault moves. That's the branch I'd chase this week. On “catalyst efficiency code but car drives normally,” that was the fork that mattered for me. Stop there until you know. If your situation is the opposite, ignore me. If the story changes I'll post the new data.

Start with the test that can prove you wrong. A pressure test beats staring at a dry driveway if the 2024 Acura MDX is losing coolant with no puddle. Don't erase codes until someone who can help has seen them. No need to make it theatrical. Might be overthinking it, but I'd rather overthink than overspend.

Tried a second charger / second scan and the story on the 2024 Acura MDX didn't change. I'd rather look cautious in this thread than stuck later.

I'd want a measurement, not a hunch. Move a coil or plug on the 2024 Acura MDX if it's cylinder-specific and see whether the code follows. You'll know quickly if you're on the wrong tree. A shop burned me once by skipping that step. I refuse to clear codes until someone else sees them.