Hello, I hope someone can help me. I have a Audi A3 1.6 petrol. There been a slight problem recently, there isn’t much power in her at all my 1.4 petrol golf would beat it any day but there isn’t much power at all, if I go above 3000 revs an lift my foot of the accelerator there’s like a rattle/grind noise. At first I thought it was my clutch/gearbox but after listening an have a play it’s just when I lift my foot off the accelerator. I’ve been told it can be the cat or it’s the engine. Also when I’m stationary it judders. I just need some help sorting this. Thank you in advance