Alright I have a 2000 Civic EX with just under 100,000 miles. Recently the car has been making this weird noise that has gotten annoying. The noise only appears when under acceleration. When the car is idling the noise is not there. As soon as I drive the car down the road and get on the gas the noise appears. If I really step on it, the noise appears to go away.

At first I thought it was an exhaust leak, as I had put a header on the car about 3 months ago, but the noise wasn't there until recently. I checked all the bolts and everthing is tight. It's almost like there is a leak somewhere.

It's like a whistle/clattering sound. I know this isn't much help, but I can try to record it. I'm thinking it could be vaccum leak. The car is going in for the timing belt and water pump to be changed in a couple weeks. Just trying to figure out what the hell it is before the dealer rakes me over the coals.

 

whistle/clatter??? I'd check your heatshields...strip em off if they're still on the car, cuz if they're not rattling now they will be soon! What RPMS is this noise happening? Full throttle or part throttle? what about coasting down?

 

The heat shield was removed when I put the header on. I'd have to say the noise is right around 1,000-3,000 RPM. As soon as I let off the gas it goes away, if I step on it hard you can't hear it. It does it through every gear. As soon as it shifts into the next gear the noise is there.

If I am coasting the noise is gone....it's on when I give it gas.

 

damn nvm i was gonna say if its a whisle kinda noise its probly the fuel rail ..i love that noise but ya anyways i have no idea ....good luck finding it tho

 

Thinking it might be the alternator. Noticed the noise is more of a clatter and recently the car hasn't started as quick as it normally did. Plus with the air on, it really seems to drop the RPM's way down. The battery is brand new. Just thinking with the noise coming when under higher rpm's, that maybe a bearing is going out?

Car goes in on Monday for the timing belt and water pump to be replaced. Water Pump, Timing Belt and all new fluid for 445.00 bucks. Not to bad of a deal