GSX with a odd knock around 3k RPMs

[eclpsed]

Here is the problem.. my GFs 1999 GSX with 80k(ish) miles has a knocking sound. when you drive the car under 3k in RPMs you dont hear anything.... it drives fine, up until you hit 3k+ you'll hear a loud knock, sometimes the knock wont be there but most of the time it is.... if you slam the clutch it stops. My friend said it could be bad gas, someone else said it was about to blow the motor. I dont know much about the 4g63 motor so im tuning to you guys as i dont wanna take it to a shop and get rippped off. anyone who can help me out? please contact me on AIM my name is eclpsed on there thanks much!!

PS if you want to hear it in person the car is in VA beach, VA. thanks!

email: [email protected]
AIM: eclpsed

 

[Strm Trpr]

Is the knocking say twice as fast as the motor's rpms?
If so, I'd bet its one of three balance shaft bearings about to seize in the engine and cause all sorts of havoc.
Sorry man, wish I could help but I'm on the West Coast.... Good Luck.

 

[1fast97gsx]

It could be anything, we'd need a better description. My car had a very similar problem and it was just as simple as an exhaust bolt being a bit loose so the downpipe was making a "knocking" noise.