Brian Roberts

Hey guys - first post here. I want to say, I've read a lot here already and I am stoked with how helpful and nice everyone is!

Anyways,

purchased a 2002 c5 z06 with 39k miles last weekend.

If I'm in first or 2nd gear, light-on -the-gas going 5 - 15 mph, at a constant rate. Then, I let off the gas, and naturally the car slows as the engine cuts gas, and it leans forward a bit, and there is a slight knock and creak underneath. Its a single noise, and its quiet, about as much noise as tapping your finger on the dash. Then, when reengaging the throttle (clutch is not disengaged in this process), the car leans back as it accelerates, naturally. And the creak happens again.

Perhaps the driveline is slightly loose, and so its rocking to the left on cutting of throttle, and back to the right when I give it gas again?

This doesnt seem to happen at speed, like on the freeway. Sometimes I can kind of hear it in 3rd, but to a lesser extent.

From some research I've done, I think it could also be the sway bar? Does anyone else have this in their c5 zo6? The driveline still feels very tight - but if I could eliminate this noise, the car may be truly flawless. Incredible machines - especially coming from a 2.5 litre bmw z3!

drivejumpfly

If it is the sway bar or the lowering bolts it is a quick easy fix. Test the noise by pushing down on the front fenders of the car like I do in this video. If that is the noise then grease the sway bar bushings.

Chicago1

Another trick is to wrap teflon tape around the sway bar that the bushing goes into. You won't ever have to grease that area again once you do.

drivejumpfly

Did you figure out what was causing the noise?

CapslockAnt

Wondering if you figured it out as well. I just purchased a 2002 C5 Z06 with 107K that has the exact same symptoms. After letting off the gas pedal in 1st and 2nd, the car makes a tapping sound that comes from the undercarriage somewhere.

ttchybrid

Does this also happen when you start moving from a complete stop ?? If so, you have loose rear axle nuts.

CapslockAnt

Now that I think about it, it's actually more noticeable when accelerating at low speeds. Not so much at a complete stop, but if I'm at a slow roll (~5PM) and then press the gas and let off, it almost rocks forward and backwards and makes a knocking noise.

Brian Roberts

Yea my sound is identical to what you describe. I'm not too worried about it at this point. The car feels very solid, and the noise is faint. Its just par for the course with 15 year old rubber bushings, I imagine.