I just bought a g35x and it has 39 k miles and wanted to do an oil change.
i was wondering is it safe to flush the engine with a gunk remover before the oil change

 

Since you intend to do this call your local Infiniti dealership and ask them
if they do this and how much. Then call an oil change/lube company and
inquire about flushing the engine, and how much. What ever you decide
change the oil to a quality synthetic like Mobil 1 5W/30. That in itself will
clean the gunk (if there is any) from your engine.

 

Be careful, I have seen the oil pickup screen clog up when this is done.

 

I would replace one quart of oil with one quart of tranny fluid and hi rev the engine for several minutes. This brakes up some sludge in the engine. And then do a regular oil change with filter and everything.

 

Try the amsoil engine flush: http://www.amsoil.com/storefront/aef.aspx