Rugged driving at all speeds S80

Hello together, From the older posts I unfortunately did not get smart, I hope you can help me. I have the problem since our vacation… If I drive for example on the highway constantly the same speed, the gas goes away at once, only for a small fraction of a second. This about every 10 seconds. I switched off the air conditioning. The same applies even if I drive with the cruise control, no matter at any speed. I drive a S80 T6 BJ 2001 110000 km. Service was made recently. The only thing I noticed were the ABS messages that have been piled up lately…. (But I return to the warm weather 🙂 ) Gruss Umbro