It's something I've noticed a lot with new cars, but my last Renault was so old (1989 R5 GTE, <dreamy sigh>) it didn't suffer the problem. When you're in neutral and you rev the engine up for a moment it takes so very, very long for the revs to die down. It's the cause, I think, of my shifting problems: I can't get used to the revs not dropping fast enough for the gear change, and the revs are always mismatched for the new gear. I suppose I could shift slower, but I'd rather not coast down the freeway for two seconds waiting for the revs to fall.
What causes it? Is it something that can be adjusted/fixed?
I've gotten a couple of responses
suggesting it may be illegal to stop it from doing this, and that in any case it would probably require changes made to the ECU.
Is this the case? The list of things that bug me about my beloved 225 is short, this is 50% of it. (other 50%: the windshield's hard to clean inside, grr).
Any information would be appreciated.