my infiniti g35 fuel gauge is acting all weird as it shows wrong amount of fuel and as i drive it the fuel gauge rises showing me the wrong amount of fuel

 

Follow the steps in the factory service manual to test for proper resistance from the connector on top of the fuel pump (under the rear seat) it should vary from 3-43 / 3-80 depending on which connector you probe. If the fuel pump is sending the correct resistance then the issue likes in either the wiring or the combination meter (which is prone to failure).

http://www.nicoclub.com/archives/inf...e-manuals.html

Start with section DI Driver Information to troubleshoot the harness, pages 16,17. Page 18 for removal of the combination meter.
Section FL for fuel pump REPLACEMENT if needed.