Chrysler Repair: 1999 Chrysler Concorde, 1999 chrysler concorde, chrysler concorde

Question
QUESTION: I have a 1999 Concorde with the 3.2L V6.  In these times of very expensive gasoline my wife and I have been carpooling and our mileage is horrible.  We are lucky to get 20 mpg (mostly freeway driving)!  The computer is throwing code P0171.  The idle is mostly smooth (occasionally at stoplights it will have a slight shimmy, but there's no real pattern as to how it will idle).  Any ideas on what I need to be looking at?

ANSWER: have a tech look at it  the 171 code  is the issue  there is a list of about 15 different things that can be the cause of this

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QUESTION: What are the 15 different items it could be?  Is one more plausible than the other?  What items could I check to either rule out or fix the problem?  All 4 oxygen sensors have been replaced, along with both the cam and crank sensor.  What other sensors do I want to think about looking at and/or testing?

Answer
Symptom List:
P0171-1/1 FUEL SYSTEM LEAN
P0174-2/1 FUEL SYSTEM LEAN
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be P0171-1/1 FUEL SYSTEM LEAN.
When Monitored and Set Condition:
P0171-1/1 FUEL SYSTEM LEAN
When Monitored: With the engine running in closed loop mode, the ambient/battery
temperature above 20 deg. F and altitude below 8000 ft.
Set Condition: If the PCM multiplies short term compensation by long term adaptive and
a certain percentage is exceeded for two trips, a freeze frame is stored, the MIL illuminates
and a trouble code is stored.
P0174-2/1 FUEL SYSTEM LEAN
When Monitored: With the engine running in closed loop mode, the ambient/battery
temperature above 20 deg. F and altitude below 8000 ft.
Set Condition: If the PCM multiplies short term compensation by long term adaptive and
a certain percentage is exceeded for two trips, a freeze frame is stored, the MIL illuminates
and a trouble code is stored.
POSSIBLE CAUSES
ENGINE MECHANICAL PROBLEM
FUEL FILTER/PRESSURE REGULATOR (HIGH)
FUEL PUMP CAPACITY (VOLUME) OUT OF SPECS
HIGH RESISTANCE IN THE FUEL PUMP RELAY OUTPUT CIRCUIT
FUEL PUMP INLET STRAINER PLUGGED
TPS VOLTAGE CHANGE NOT SMOOTH
TPS VOLTAGE GREATER THAN 0.92 VOLTS WITH THROTTLE CLOSED
HIGH RESISTANCE IN THE FUEL PUMP GROUND CIRCUIT
FUEL PUMP MODULE
KINKED/RESTRICTED FUEL SUPPLY LINE
ECT SENSOR (OUT OF CALIBRATION)
MAP SENSOR (OUT OF CALIBRATION