Is it showing you any kind of symptoms at all? Any knocking, rough idle, does not rev up too well??? Have you pulled any of the plugs on that bank yet?
Are they talking about the first cyliner when they say bank 1? The car was running a little weird, (slower, and felt like it was missing a little bit) but i had the code erased and it hasnt come back on yet
"Bank 1" is refered to the # 1 cyl. which on the v6 stang the # 1 cyl. is loc. on the passanger side.
-DTC 171 (Fuel System Too Lean)
Now what this means is that you are running too lean on the # 1 cyl. side (pasgr side). Your O2 sensor which is on the exhaust manifold is sensing too much air passing by. This could be a "vacum leak" somewhere in your exhaust manifold. Your stang is just sucking in extra unmeasured air, wich is one of the causes for the 171 DTC to be set. Check your exhaust manifold or headers, check the exhaust gaskets, the bolts, nuts & washers make sure they are tight, listen for leaks, use soapy water in a spray bottle. Remember that a hole in your exhaust the size of a "pin-hole" can cause a lean condition!
Hopefully this can help you, this is from expierence on my 01' v6 stang, same problems, same DTC's till i found out my exhaust manifold was cacked on the bottom, tiny little crack.
I have a 2001 Base 3.8l automatic and it was running good all day one day, until I went to pull away from a stop sign and barely got on it. Next thing I know is my stang made an awful noise, then was completely weak. It felt like it lost all horsepower and began to hiss real loud from the back passenger side of the motor. I'm guessing it is coming from somewhere in my exhaust system. The car keeps acting like it wants to sputter out and when It's parked it idles very rough, and it sounds terrible when I rev it up. I had checked the fuel filter first it was fine, then I replaced all plugs, plug wires, and coil pack, still ran the same. So I had a buddy come and run the codes with his OBDII reader. The only codes it showed was something with the EGR valve, Random misfire on Cylinder #2, and the Throttle position sensor. What all should I do to get my ole car back running again???? Oh and by the way when I bought the car it already had the exhaust tip ripped off and the muffler was pretty much dragging and I had caught the muffler on stuff a lot before I ever got it rigged to where it wouldn't drag anymore. So I think my exhaust could be coming apart somewhere. Could a leak in my exhaust cause the rough idle and loss of horsepower???