Fuel system running lean on bank 1 & 2

Originally Posted by Icebrand

2010 370z Touring Roadster 38K

Banks 1 and 2 are running lean.
Codes P0171 and P0174 were thrown.
Probably causes were listed as:

Low Fuel pressure
Blocked injectors
Large vacuum leak
Mass air flow sensor fault


The car has the pickup of a ford pinto. Revving the engine in gear beyond 3,000 rpms results in no increase in power. I can't imagine both MAFs faulting at the same time. Air filters needed to be changed, so I did, disconnected the battery to let the computer reset, check engine light stayed off, but no change in performance. I can only imagine at this point that the fuel pump is covered in debris, or the injectors need to be pulled and cleaned.

The car is driven by my girlfriend who drives like an old lady in an Oldsmobile. I changed the battery in the car for her once and she never accelerates hard so the the computer never learned the range of throttle, and it ended up idling strange and sputtering forward when accelerating. I let it idle until warm, revved the engine into the 6k range several times, computer learned the range of throttle. problem solved. I am wondering if her grandma driving habits are the underlying cause of this leaned-out fuel system, and if the injectors are the likely cause.

We always use good gas, either Texaco or Shell.

Any input is appreciated. Thank you.

Originally Posted by fuct

i dont really think this is true. after you reset the battery you dont have to drive it hard for the engine to relearn anything.


most likely it sounds like crappy gas, clogged injectors, or a fuel pump issue. my fuel pump died at 40k miles.