98 grand am O2 sensor

Ok heres another question: Check engine light came on, had it checked and came up saying " bank 1 sensor 2". Had the O2 sensor changed prior to this, bank 1 sensor 1 assuming, since I am not the one who did it, was a friend. Is bank 2 the same as sensor 2 in bank 1? Sorry for the confusion, never been a mechanic person. The shop just replaced O2 sensor for bank 2. Now wondering what the hell that means! Totally lost.
Anyone clarify this please. Hoping Im not gonna have to go out and spend more $$$ to have another O2 sensor replaced! My car is still missin, acts like it wants to stall when going speeds around 40-50 mph. Was told that this was all due to the O2 sensor! :banghead:

Hey armybrat! Well they probley replaced the one under the car behind the catalitic converter last. and the one under the hood the first time. yes there's two. they check for the amount of O2 in the exhaust. the first one, under hood, control air/fuel mixture by adding more fuel(lean low voltage) and rich fuel mix(higher voltage from O2). the true mix of air and fuel should be around 14.7 parts air to 1 part fuel for max fuel economy and performance.

Sorry if that was information overload. If u still have a rough running car and Both O2's been replaced it could be the converter needs replaced. But bad plugs/wires can also cause the miss and rough running and so can the fuel system. Have u changed or had changed the fuel filter? Hope this clarifies ur conundrum.

If computer says Bank 2 I am assuming you have a V6. BANK 1 =ex. Manifold 1, Bank 2 = ex. Manifold 2. Sensor 1 = Front, Sensor 2 = Post-Cat. A V6 May have upto 4 O2 Sensors, most only have 3. (2pre- Cat-converter, 1post-cat-converter)