Vibration around 1800-2000 rpm

[ckgulec]

I have a 2001 Jetta 2.0 (manual) and having a couple of problems with the car. I appreciate if someone gives some advice.

The first one is, I can feel some vibration around 1800 to 2000 rpm as I accelerate especially on the 2nd and 3rd gears. Can it be a transmission problem since it happens on different gears but similar RPMs?

The second one is a perfomance problem. I think the engine is way too noisy and sluggish as I accelerate. Especially around 2500-3000 rpms it is to noisy as if there is a problem with the muffler (but the muffler is ok). I think the car cannot perform as it is supposed to. I know this sounds very general but that's all I have for now.

By the way, check engine light is not on.

Thanks.