I have a 2006 115bhp focus ghia.
I brought it into the dealer and got it serviced. The said they could find nothing wrong. When I drove it home it was losing power when going uphill on the motorway. It lost 10kph on some hills in 5th gear.
I recently bought bridgestone A001 all weather tyres.
Would tyres cause this, I was thinking of asking for a compression test.