Vacuum leaks are not common. You can try spraying brake cleaner around the pipes. If there’s a leak, the revs will change.
I already advised you that it is likely to be your lambda sensor.
I you’re 15 years too late to be asking Renault to step in and sort it.
To me, it seems like you have 2 viable options.
1, learn how to drive around it
2, get an aftermarket remap
Just to add, I’ve had this and it was the throttle body (as has one of my other trackday friends)
Front Lambda can also cause misfires with no code, but it’s generally 3-4000rpm and upwards when they start to miss.
Lateral sensors are in the B pillar (95% certain).
Definitely nothing to do with the seats.
You should be able to find where the cables tee off the loom on each side.
Ok that makes more sense. Just be wary of messing too much. Blyton is terrible for outside wear. Lots of lefts and no time for the rubber to cool.
I think the only tyre I’ve used there which I’ve not killed, was MRF’s.