The car in question is 2017 Kia Ceed with 1.6 GDI petrol engine.
Lately, I noticed a wierd noise coming out of the engine. As I'm accelerating, up to around 3200-3300 RPM everything sounds fine. Above 4000 RPM the engine also sounds fine.
However, in between those 2, at 3300-4000 RPM roughly, engine sounds like, for a lack of better word, "gurgling" or like I have a V8 in there.
Also, I have noticed the car is lacking power in the higher RPM ranges compared to what it felt before.
It was serviced 2 months ago at the dealership, so if anything, this proably is a recent fault.
I tried checking if it's maybe a hole in the exhaust system, but couldn't locate any.
What else could be the cause?