Hey guys.
I'm Stefan from south africa. i have a 2004 audi A4 1.8T. A few months ago i have removed the cat and done the software on the car, i have also replaced the turbo and serviced the car. a few days ago i picked up that the car jerks between 4000 and 5000 rpm. the funny thing is that it only starts above 150 kmh the closer i get to 200 kmh the more aggressive it gets. I took it p to 240 kmh but still doesn't go away.
If i put the car in manuel and i drive it, and lets say third gear and i keep it in that gear till i get up to 4-5000 rpm it does not happen, only when over 150 kmh.it jerks and you can see the rev counter jumping as well.
Can you please advise me on what to do.