I had a recent incident where I found on starting a journey that power steering had disappeared. I was really worried as I was over 100 miles away from home; however, after stopping to look at the handbook (which wasn't very helpful) I was mega relieved to find that when I started off again the power steering had come back. However, is this something I need to get checked out? The only possible cause I could think of was that I was parked in a car park with a loose, rough surface so I wondered whether something might have got into the mechanism. The car is a Toyota Corolla.