Complete loss of power after exiting motorway
 

Hi,
This has happened three times in last couple of months! It would usually involve a trip on the motorway or a national speed limit road. My 2001 Volvo S80 auto/petrol 2.4 would simply lose power after exiting the motorway and driving at a much lower speed. The first time it happened it was on a straight stretch of road 30 mph I slowed down for the cars in front and as I attempted to pickup speed again the engine simply switched off completely. All electronics came on the dash board even the air conditioning was still blowing, but I simply had no drive and the steering became very heavy. I simply stopped to the left, applied hazard lights and put the gear stick in park position and turned the ignition to off position. I attempted to restart the car and it started straight away and drive off straight away! The second time it was also after a motorway trip but this time it did the same thing upon taking a right turn after stopping at a traffic light. Last week also the same problem but this time I was turning left after considerably dropping my speed from 60/mph to 30/mph. On all three occasions the car restarts and drives off straight away without any issues. I must admit I didn't give much thought when it happened the first time but I am worried since it happened twice again. The car was fully serviced last January and it is not showing any error codes! I do not want to take it to a garage and have the mechanics throwing guesses at me.
I would appreciate feedback from anyone who had or heard about a similar problem before.

get codes read and try a new fuel filter check all earth points and your battery connections

How many miles on your '01?
Turbo or not? (maybe all S80's are turbo, I don't know?)
Deffo on getting the/any codes read.

I too think any vehicle's fuel filter is worth changing when its age is unknown and these power drop outs occur.

See if the ETM is dirty.

See that your transmission's fluid is clean. I believe neglected fluid can cause them to fail to unlock or some such upon pronounced deceleration.
Someone with more knowledge is welcome to add to that.