Modern Vespa

So I've had the new 310 for nearly 6 months and done 2,400km. I'm riding it more now as the summer is here! My problem is when I'm riding at a constant speed and not moving the throttle position at all, occasionally the revs slightly drop and the speed slightly reduces, nothing much but enough for me to notice - 2 or 4 kmph. I can accelerate again and it's fine but it's annoying me! I will take it to the dealer but wondered if anyone has had a similar problem or any ideas? It's not when I'm going flat out, often notice it more at around 100kmph or 110kmph (Vespa Speedo!). A friend said maybe the traction control but I've tried it with that on and off and there is no difference. I thought maybe throttle cable (if these still exist! Or fuel injectors), and of course the worse part - it's "intermittent" so not always happening!!
Cheers.

There's a thread on the German forum that sounds similar

https://vespaforum-de.translate.goog/viewtopic.php?f=15&t=65597&sid=50e643387e6e76ffa199154f66038bee&_x_tr_sl=auto&_x_tr_tl=en&_x_tr_hl=en-US&_x_tr_pto=wapp

Thanks SteelBytes I've just read through all of that thread.

Good news - seems to be a fault that quite a few people have mentioned.
Bad news - no fix yet!

I did see some mentioned about the belt maybe slightly slipping and others with various different thoughts. I'll get it booked in the with dealer and see what he says.

New post on the German forum

https://vespaforum.de/viewtopic.php?f=15&t=65597&sid=d505edcca4ddb9073af02831acc551b4&start=165

(Google translate)

Thanks SteelBytes, this is REALLY useful.
I booked it in with the dealer and it went in last week. Needless to say, they couldn't find anything wrong except both the tyres were very low pressure. They said that will be the reason but I've since tested it again and the problem remains - it's so frustrating so I was really pleased to see that hopefully there is a simple solution.
I'm going to take it back to the dealer again and ask him to check the Lambda sensor connections.... I've got my fingers crossed!

FYI it's only one person who has said this. No proof for or against.

And who knows - just re-making the connections may have cured an intermittency.

I guess my first step now is getting my dealer to experience the issue, he's only tested it for this one and didn't feel it. I know I mentioned it before, but because it's an intermittent problem it really is the worst - when you want the problem to occur, it doesn't! 😵‍💫

Yeah nah.

Roughly said, the sensors perform different roles. First is for the fuel trim and the second is for checking the cat health. ie the ecu will treat the two signals differently