Hey all, hoping i can get some help w/ my G35X. I got an 06' G35X with about 138k miles about a year and a half ago, been running alright, fun car to drive as a first car. Haven't really had many issues come up asides from having to replace the power steering hose and replacing a failing starter. Its got a valve cover gasket leak which im about to have replaced soon. But my fuel economy i feel like has always been pretty low. I do about 95% city driving but even at the start i was getting around 11-12mpg. But up until recently the car has been feeling heavy when driving low speeds (under 25mph), startups feel like its choking up on fuel when cranking, and i can smell fuel coming through the air vents and exhaust. Got two new codes come up when this all started, P0138 and P0158 which i assume has to do with the fuel running rich flagging the two bank sensors. Havent driven it in about a month and a half since my fuel economy dropped to around 8-9mpg and with gas prices and im not trying to drop $55 a week to fill up. Does anyone has any idea or suggestions as to what could be the main problem? Im pretty new to the community so forgive me if i missed any information or if im just wording anything weird. Thanks!!

 

Have you smoke tested the intake or checked the exhaust for leaks?