toyota corolla 2002 code p0171
on 2002 Toyota Corolla

check engine light

Asked by for the 2002 Toyota Corolla
po171-bank 1 system lean.Start by checking for vacuum leaks.Don't fall for the oxygen sensor diagnosis that many parts stores have told many of my customers.9 times out of 10 it is a vacuum leak.
1 more answer
in agreement w/ bmdouble as most likely-will add contaminated maf sensor/restricted fuel filter as other possibilities if no vacuum leaks are found.