I have done a dozen of this vehicles and by experience I can tell you to never ever touch this throttle body unless they have been cleaned regularly every so often. vehicles with too many miles should not be touched. however I know how to fix this issues if none of the resets and relearns works. all you have to do is to flash the ecm and it will be taken care of. in order to do this flashing you will have to have a passthru and the Nissan software name NERS  which is not free, it cost 270 usd  unless you can get one on the side like from mhhauto.com, cartecnology.co.uk etc, a sub must be purchase from Nissantechinfo.com, no way around that one. its only 19.95 though, and  just flash the ecm with the correct flash. note  you must read the ecm part number with your scantool in order to know which calibration number to buy.  look in youtube , its a good source of info in many cases.