Could you post a video with audio?  It's difficult to say definitively without hearing it.  In general the biggest problem is not muting the string effectively when you release pressure to get to the next string you are sweeping.  It could also be that your fingers & picking are not exactly synchronized as you go faster.

Also, if you are using an electric guitar with a gain tone, you might have the gain set too high on your amp causing a lot of unwanted extra sound.

You said you watched my sweeping tutorials.  I have 6 of them at various skill levels.  Which one are you working on?

Hope that helps!