Ok i have not long owned this audi s3 2001 the car has been running fine as standard however not as quick as i would of expected from the car before buying it i have never drove another one so i was guessing this was the performance of these cars dont get me wrong it isnt slow just not what id expected. Anyways not long after buying the car the exsaust had came lose from the turbo causing it to blow the car still ran fine apart from the blowing noise. I got someone to do it but he said someone has had a new turbo on and has rounded the nuts he has tightened them back up again but see how it goes. Ok it was going fine for few weeks then i booked the car in for remap the day it was going in the exsaust came loose again i should of not bothered with the map but i did not want to let anyone down so thought i would still get it done knowing the exsaust was not a major issue. After driving away from the remap the car was missfiring when you gave it loads of throttle so i rang up the guy who remapped it and he blamed the exsaust and could not do anything till it was sorted. by the time i got the car home it was running very slow, the next day i got the exsaust sorted but i also bypassed the cat as i suspected it was gone as it always had a rattle from it and this would explain the poor performance. After the car was back together the car stilldrove slow for a couple of miles then it started running fast with loads of missfires after that the missfires were settling down to hardly none and was driving really well for about 5 miles. Then the traction control light came on and it lost all power again and has been like this since. I Have now had the original map put back in the car but i still have this traction control light coming on about half a mile after a drive it and costant no power. I have had a diagnostic done and its saying mass air flow meter but will this be the problem as it all started after the remappcan anyone please give advice?