Megane 1.3 TCE shaking problem at idle

[mfestt]

My car is a 2019 Megane 1.3 TCE, manual, with 140,000 km on it and Joy Pack.
I took my car in for routine maintenance in April, and when I got it back that afternoon, it started vibrating while idling.
It hadn't happened before.
The mechanic added 5w30 RN 720 oil.
I suspected the oil and had Motul RN17 oil added back, but the problem didn't go away.
The injectors were cleaned, and the problem persisted.
The idling vibration didn't go away.
Another car owner has the same problem, and they replaced the pulleys, flywheel, and engine mounts at the authorized service center, but the problem remains the same.
The vibration doesn't go away.
The spark plugs were replaced, and the problem remains the same.
What could be causing this vibration?

[mickthemaverick]

Is this an audible engine vibration or a whole body shuddering?
Just top of the head thoughts, have you checked the exhaust system mounts and manifod heat shields?

[mfestt]

No, it's not audible; it just vibrates the body. The injectors and spark plugs are healthy.

[Rp0thejester]

At that age it sounds unlikely but I'm going to suggest an engine mount rubber that has perished. Can't think of anything else that could vibrate the car at idle. Only other possible thing is the crank shaft. Is it a quick or slow vibrate through the car? I've only suggested those as I'm assuming you've checked every bolt for tightness including exhaust brackets/mountings.

[mfestt]

At that age it sounds unlikely but I'm going to suggest an engine mount rubber that has perished. Can't think of anything else that could vibrate the car at idle. Only other possible thing is the crank shaft. Is it a quick or slow vibrate through the car? I've only suggested those as I'm assuming you've checked every bolt for tightness including exhaust brackets/mountings.

There is a slight vibration that makes the chassis vibrate. At first, I thought it was from the injectors and spark plugs, but it was not. I also did not check the brackets. How can I check them?

[Rp0thejester]

I'm don't know where the engine mounts are on a Megane, I'm sure Google can help, perished rubber could possibly be the cause. Worth a look. If the engine knocks/thuds when changing gear at speed then it would point to that and needs immediate replacement.

[mickthemaverick]

You might get some ideas from this video:

[Rp0thejester]

Thanks Mick, I forgot to do it with an Irish accent...

[mfestt]

I checked, assuming it wasn't an engine mount.

I connected it to the computer and queried the injection parameters. Combustion Malfunction Counter: 65353 → This value seems high, which may indicate that the counter in the ECU has reached its maximum value. There could be a coil/spark plug or injector fault; I need to measure each cylinder separately for a complete solution.