Peugeot 3008 Cruise Control slipping

[Juggins]

Hi,
Peugeot 3008 62 plate 65K miles
I set the cruise control to 70mph and it stays at that speed up or down hills.
If I put the cruise on 'pause', either by pressing the side button (cruise stack) or using the brake/clutch and go down by 10mph (to 60ish) and then just engage the cruise with the side button.
It engages but then the rev's go from about 1800 rpm to 2500 rpm (in seconds), as if you are doing a foot down acceleration (or a bad clutch change), and then the cruise revert back to 'pause'.
If I do the above and then set the cruise to (say) 60mph and that's fine but use the side button the increase the speed back to 70mph, the increase goes 61, 65 then 70 - as it should but the same thing happens as above.
If i slowly take the speed up individually - then i don't get the problem.
Have also tried this at lower speeds and still the same problem.
I have connected an OBDI and looked for any fault codes but no codes (on anything).
Any idea on what to do? Would it be a clutch problem?

[xantia_v6]

I can only suggest a slipping clutch. If you push the accelerator to the floor in top gear, do you get the same slipping effect?

[Juggins]

Hi xantia_v6,
I did a trial of this during my commute to work and yes. The revs go up as described and then head back after about 1 or 2 seconds.

[RichardW]

Clutch is worn out....