Weird tremolo sound at higher frets w/distortion

grab the string between two fingers (or hook under it with one), pull it out and away from the guitar, then let it go. this is usually called popping. in many situations, it's easier to grab (with two fingers) the string on a guitar. on a bass, most players hook it.

Gnease,

I tried popping the string and I can't really tell if it's worse or not. It's not noticeably worse I don't think. Either way, I had a feeling it might be the trem too. I'm guessing trem springs aren't standard. Do you just pick them up at your local store or can you somehow order them from the manufacturer?