I have an a3 1.8T AGU, recently had i chipped, car runs great and pulls very hard now, holding 16psi of boost now, however if i let the car idle right down and blip the throttle the car hesitates slightly, cant notice when driving accept when going down a hill, if you come back on the power i jerks. Also i think it may be running rich as i inspected the plugs and they were dry but black, if running the car on the drive for a bit i get nice black marks on my drive from exhaust. However the car is fine when driving, feels smooth and no hesitation. Cleaned maf, it had a new one last march. Any advice would be great.