I have a 96 Civic Ex and every time I hit about 2500+ rpms the engine changes noises from a normal rev to like a rattling rev. I think it has to do with the v-tec but I am not sure.

 

Thats not vtec. A sound clip would help.

 

Auto or manual?

 

Do you have an aftermarket exhaust on it?

 

Mainshaft bearing (transmission), just my initial guess without hearing it first hand.

 

Most likely your exhaust, get underneath your car and pound your resonators and cat with your hand. You'll probably hear a weird sound. replace whichever one sounds like there is loose material inside. Noise will go away instantly.

 

^my muffler was doing that, then I ran over some **** and it plopped off. I still haven't cut the hangers off, though. I went back and picked up my muffler lol.. I should really cut the hangers off sometime.

and now my defacto straight pipe rattles against the rear swaybar. Its pretty annoying, once in a while I can adjust it (kick it) and it'l go away for a while. I really need a nice custom exhaust..

 

It's a manual, and it has a stock exhaust.

 

Probably an exhaust leak somewhere

 

Does the car stutter and the engine lose power? Or is this simply just a sound?

 

na man i have the same problem my 97 acura integra (no vtec)

 

Check the exhaust heat shields.

 

Post your issue in the Integra forum.

 

Not trying to thread jack but having a similar issue as we'll, but I do have a aftermarket exhaust, when I hit 3500 rpms on a cold start it instantly turns raspy, tell it warms up. Mind you the exhaust is very throaty and gives no rasp only on cold start. So would really like to see what's the culprit, I was thinking maybe cracked exhaust manifold.