i searched a bit but they seem to be different issues.

Just picked up an auto 07 G35 yesterday with 40k miles. at startup for a minute or so theres a loud ticking that does increase with RPMs. its annoying and id like to have it taken care of if possible jsut in case it leads to something major. all fluid levels are good and nothing looks out of place. any ideas before i take it to the dealer?

Sounds like it could be the Timing Chain.

wait 30 mins after shutting engine off and check your oil level.

lifters most likely got the same problem

I had the same issue.. was one of of the belts... had it changed at 50k tho..

Could be the fuel damper on passenger side in engine compartment ticking.
TSB # ITB06-012

Yeah I purchased a G35 on Thursday July 2nd 09 and the ticking noise that the dealer said was probably the timing chain tensioner was probably more like a bad rod bearing. I made it 232 miles b4 it came apart on the highway. Blew a piston rod through the engine block and my car bled out on the highway. Oil everywhere on the highway. Hopefully i get a new engine under warranty, but wont know till monday. glad I didnt trade my other car in so at least i got something to drive the rest of the weekend!

how was that oil level?

oil is dead on. the ticking only last for a few seconds but im sure its not supposed to be there so it bugs me

Exhaust leak?

any ticking is bad, get it checked out asap instead of guessing.