only that code???????
which engine? of the 3. (ill pretend 4 liter I-6,)
how many miles one engine, and do you service it? fully?
the fsm covers this. need that?
171 is lean AFR. lean AIR/FUEL/RATIO. (or lean fuel mix)
it means the 02 front sensor B1S1 is lean.
the fsm lists 10 causes after a new 02 , dont cure it.
first is low fuel pressure.
in geek speak (ASE) it means fuel trim show gross lean.
the OBD2 systems have trim level trip points.
if you were to scan the PCM youd see LTFT way the heck off.
and id fix that first.
the 171 means the 02 is stuck at 0v. super lean.
or is shifted lean,, only looking at it with a scope or scan tool shows
you what it is DOING.
if stuck at 0v, idling, its bad, the sensor or there is and exhaust leak
allowing outside 20% oxygen to hit this sensor and slam it horrid lean for ever.
that is why you just scan it and look. not just a useless code reader.
good scan tools you can scan and graph the 02,
and see this.
if i dont see this, i then work this full time. with a battery of tests.
there are many causes.. over 20.
see blue line in the full scan graph?
we can scan and graph 12 values at once, 1996 car too. any car.
see DSO photos(scope)
the full manual is here chapter 9 cover this 100%
me,. i try an new 02 , and with that i know it can't lie.
and then use the to find why.
weak MAF (Dirty)
intake leaks (maf engines)
exhaust cracks. hoepless this.
gross misfire sends 20% oxgen down stream, so i look for misfire like a hawk. felt , heard or see engine shake that is misfire.
low fuel pressure 58psi is good.
those are the big ones.
btw, if a V6? or other V engine
a bad maf will cause both banks to go lean. (mines a 3.8L v6)
so.............. no engine stated, no details....