Hello, I have a 1992 Audi 100 C4. The engine is fine, however sometimes if I put my foot down when it's idling at 0.9k revs it like struggles to get up to 2k, well it doesn't 'struggle' but it sounds like it stutters for abit and then the air intake will pop, from what I think is a back firing/miss fire. After 2K it's sound as a pound

Anyone know what that is?

Also, my engine is AAD, and its got the injectors and air flow meter on top of the bloody air filter box, is there an easy way to replace the air filter as I don't think it's EVER been changed. Or can only a mechanic do it?

IF anyone else has AAD engine and has changed air filter themselves please tell me what to do as it looks really hard