2001 Questions for all other cars power loss

Engine Performance problem
2001 Questions for all other cars Manual 52000 miles

I have got a seat leon I was on the motorway when my car lost all power, I had my foot flat dwn but there was no revs.
i swithched the car off then on but the car has no power it wont go over 3000 revs if it does it will sometimes cut out.
the epc and engine managment lights are on.
the aa saiid it was the exhaust and cat but we replaced them and it still doesn't work properly.
we callled them out a gen but they could not find a problem on the diagnostic system.