So I went to the gym and was in there for about half an hour I came out turned car on ( audi a3 1.8t 2003 aum engine, 120k miles but engine seems in good condition. Anyway, got into car and gauge was already on 90 degrees, I drove for about half a mile or so then went through 2nd gear fairly hard, then changed to 3rd and began to slow down however when I put foot down in third only about 20 percent it seemed as though the car was coughing and holding back, loss of power etc. I slowed down and tried to listen to what was happening but after 10 seconds it stopped and drove fine, I drove slowly back to mine about 5 miles and boosts fine and seems back to normal, quick check in the engine bay in the dark and everything seems fine, so any ideas or what to look for, thankyou for your time, Tom