Any advice please on this issue.

V70 2.5 diesel 2008 (205k on clock), SE LUX, manual.

Driving around 70+ (but has also done it at 10MPH) there is no acceleration (or at best 1mph more but takes it 30 seconds to get there. Then if going up slight incline at that speed on a motorway the speed will very slowly drop. This can happen when you’re in cruise and depress accelerator to overtake and no extra power or not in cruise and just go for an overtake. Can happen after literally five minutes driving or may not happen for an hour.

No noises, issues to report other than the above problem.

Stop car at services, switch engine off, have cuppa, come back and no issues. Been a problem for at least last 3 years (once every few months), now happening almost every week.

Any ideas please experts?

Recently had full Volvo service, quality diesel used and well looked after. Never used to tow anything, 90% of mileage is motorway driving with sole driver and not carrying anything.

Anyone able to point me in the direction of likely problem and fix? Many thanks.