2006 Equinox O2 sensor Where do I find it, system says too lean.

SOURCE: location of O2 sensor in bank 2, 99 5.4 expedition, running lean

I have a ford 2003 windstar that was running very rough when cold and almost stalling. engine light came on. went to autozone and they read the codes for free and told me it was running lean on Bank 2 also. i came home searched for the O2 front sensors online using the info autozone gave me. there are 2 front sensors on my car that need to be replaced at the same time. look for ones that have a direct plug in and don't need wire splicing. the ones without the wiring harness are cheaper but more of a pain, i think.
they were fairly easy to replace. getting access with the wrench was the worst. reset the light by disconnecting the battery for a few minutes. seems fine now and the light hasn't come back on.

SOURCE: PO171 error code System too lean bank 1

Here are some possible causes, I would start with anything related to replacing the intake.

Air leaks in intake manifold, exhaust pipes or exhaust manifold
Fuel control sensor is out of calibration
Low fuel pressure (fuel filter clogged, pressure regulator failure)
One or more injectors restricted or pressure regulator has failed
O2 sensors contaminated, deteriorated or has failed
Vacuum hose is disconnected, broken, leaking or loose

SOURCE: 2002 Pontac Grand Prix GTP P0171 code engine stumbling at times

Bank 1 is the frt side exhaust manifold (did they say bank 1 sensor 1?),you can start by replacing that sensor,i would check the intake for leaks ,the gm 6cly. are known for bad intake gaskets,you will see oil coming out form the frt or rear of the intake,also check your atifreeze overflow bottle for bronwish sludge,which means that the oil is mixing with the antifreeze.A leaking intake could cause that lean condition.

SOURCE: Car Running lean o2 sensor is fine.

Most likely your MAF sensor is dirty. It is a very delicate wire that reads airflow in your intake and tells the fuel distribution system how much time to open the injectors. Here's a link to some Ford ones so you know what you are looking for.

http://www.americanmuscle.com/maf.html

They can be cleaned, here's a general how too. If you google MAF Sensor clean you'll find videos and lots of helpful hints! Just make sure you remove the sensor from the vehicle and allow it to fully dry before replacing it.
Mass airflow sensors constantly measure the amount of air entering the intake manifold. This lets the engine management computer know how much gasoline to inject into the cylinders for proper combustion. Hot-wire-type sensors, like you have, work by keeping a short piece of wire or film at a constant, elevated temperature. An electrical current is applied to the wire to maintain its temperature; the amount of current necessary to maintain the temperature is proportional to the mass of cool air flowing past it. Sounds complicated, but there are no moving parts and the response rate is very fast. So far, so good.
Eventually, dirt and oily film bake onto the wire, insulating it from the cooler air--and when the engine management computer sees a value for air mass that's too far out of range, it sets an error code. Periodically, there's a cleaning cycle during which the wire is heated to a very high temperature right after engine shutdown. This burns off deposits.
When this cleaning cycle fails to remove all of the contaminants, you're supposed to replace the MAF sensor. According to almost every manufacturer, it's not recommended or even possible to clean the delicate wires. Of course, they're selling those sensors, so their motivation might be suspect. Next time, I'd try cleaning it first--what do you have to lose? I used to use aerosol carb cleaner, but CRC MAF Sensor Cleaner is new and less prone to dissolving other components in the MAF sensor. Do yourself a favor and remove the MAF sensor from the vehicle before attempting to clean it. Also, I'd make sure the air filter housing, air filter and all associated ducting are intact, clean inside and not leaking dirt. This will keep you from needing to clean or replace the MAF sensor anytime soon.

SOURCE: o2 sensor location 1997 pontiac grand am 2.4 4 cyl auto trans

BANK 1 SENSOR 1 IS THE ONE IN THE EXHAUST MANIFOLD. BANK 2 SENSOR 2 IS BELOW THE CATALYTIC CONVERTER.

P0171 SHOULD GO AWAY WITH A GOOD O2 SENSOR BUT DO CHECK FOR VACUUM LEAKS TO BE SURE. 3.1/3.4L ENGINES HAVE A BAD DESIGN INTAKE MANIFOLD GASKET, THE LEAK OIL, COOLANT, AND AIR.