Hi all I am new here and just need some advice. I have a 1.6 ghia petrol W reg focus, i recently had the water pump replaced after my alternator belt failed. 4 days after having the car back I seem to have a loss of power, mainly when going up hills. It has no acceleration and in 4th i can only get 55mph with my foot to the floor. After a few minutes or when traveled a mile or so it seems to have returned to full power. Any ideas it doesn't do it all the time so not sure what it could be. Thanks for reading.