2006 G35x sedan. Acceleration is very touchy is this normal. seems to shift hard also. Not sure if this is normal either.Also I seen other post but couldnt find them again. When shifting park to reverse it makes a loud click. Not all the time though either. If i shift back amd fourth a few times it does it once or twice. Its smooth and normal and the i get the clanking noise peridocally like something is hanging up.

 

Get it up on a lift and have someone shift reverse-drive-reverse while you check it out from underneath until you isolate the source. Probably just a bushing on the differential but loud clunks are easy to find if it's something you can reproduce.