Car "repair" question. '23 Hyundai Elantra, hybrid. First of all, engine sounds like broken muffler but only when

[3Hotdogs]

accelerating. Step on the gas while at idle, no extra sound beyond what is normal.

Coincidently, the milage has increased by 10 miles per gallon.

Thoughts?

[SheltieLover]

1. Does it run well?

Start quickly? Shift smoothly?

[3Hotdogs]

5. Yes. No other problems beyond the noise.

[waterwatcher123]

2. Noises are notoriously difficult to diagnose

You may have a brake caliper dragging (look for excessive brake dust on a wheel) or a loose or broken heat shield on the exhaust (they can make a racket). Just a starting place of common noise generators on a car. The heat shield would have no bearing on increased mileage (brakes might if not working properly).

[regrestic]

3. If there is noise

when accelerating , say a knock, then goes away, could very well be engine knock. Hard to diagnose here.. I'd get it checked out.

[3Hotdogs]

6. I recognize "knock" sound. This is not that.

[biophile]

4. Same here- 2024 Elantra hybrid

noisy on acceleration. But it seems fine otherwise and gets 60 mpg. We have had 6 Hyundai vehicles- Sonata, Elantras, and an Ioniq hybrid. Loved all of them; never have had a problem. My old hybrid did not make this noise; though, the new one does. I have not had it checked out - it’s a year old now and no other issues besides a noise that doesn’t seem to affect performance.
Your guess is as good as mine!

[3Hotdogs]

8. I've had 6 or 7 Hyundais. The only major problem was with 2018 Sonata hybrid. It began leaking coolant into the

passenger cabin --- intermittently. I took it to four repair shops and none could determine the source. Determining the source could have probably required taking the dashboard apart so that was likely in the way of finding the cause of the leak.

On a day when it wasn't leaking, I took it to the dealer and traded it in.

[CanonRay]

7. Check your motor mounts

If a mount is broken the engine can torque and lift, possibly opening the manifold causing the increased noise. I had it happen in a Chevy but in my case it pulled the accelerator to the floor while simultaneously ripping out the power steering and brake hose. Nearly got me killed. Just a guess, Im no master mechanic.