Vibration Under Acceleration

[iamherny]

just have a question which one of you guys might have the answer to, I have an R34 25gt and while driving at about 40-50km/h up a slight slant uphill i hear a rattling from the passenger side front area while in low revs while also obviously accelerating. The noise never appears to be heard when it is on a level road or down hill. I thought it was just an exhaust rattle but I've come to the conclusion in only happens uphill. I've checked my driveshaft, suspension, CV's, engine mounts, brake rotors,no chassis damage etc, nothing seems to be loose or damaged.

[scotty nm35]

Drop the cat, the honeycomb ceramic may have dislodged.

[Duncan]

when you say you hear a rattling but only up hill, does it stop immediately if you take your foot off the accelerator? And is it more likely to happen in high gears than low gears?

[iamherny]

yes it only happens when I accelerate, in 2nd and 3rd gear. My exhaust is quite loud, but i still manage to hear it from the outside, not from the drivers side, very noticeable on the passengers side. when I stop accelerating, the rattle stops. It never rattles on an even road surface. only on a slight uphill.