Sporadic power loss Volvo S70 T5

Good evening Volvo municipality For some time I have been observing the following: – Sudden strong power loss during kickdown. Like a switch during acceleration suddenly no more steam. – Motor always runs clean and starts clean. – Once the power loss has occurred it remains over the whole speed band and disappears only with a restart. – It never lights up an engine control light. – General power loss here and there. At the moment there are problems with the reading, you only get to the “gas-relevant side” which has no errors. Further diagnosis is started and all vacuum hoses are changed, which are all very weak due to the age. I would be very happy about your input. Maybe this is a case for e Oldschool Volvo mechanic/connoisseur. Greetings from Switzerland Stefan