Question I have a 1998 Grand Cherokee ZJ 4 .0L Straight engine not a V6 or V8. It has done 150,171 miles.The problem that i am experiencing is that the engine is Misfiring when idle and it has been consuming too much fuel and it is giving out smoke on it exhaust. The Diagnose scanner read Code P0171 system too lean. please tell me what to is wrong and what part or parts to change
VIN 1J4GZ58S1WC269097
Thanks
AnswerI would not toy with this unless u want to throw parts at it.
This code is not a single part or issue prob
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
TPS VOLTAGE CHANGE NOT SMOOTH
TPS VOLTAGE < 0.92 V
ECT SENSOR DEFECTIVE (OUT OF CALIBRATION)
MAP SENSOR DEFECTIVE (OUT OF CALIBRATION)
ENGINE MECHANICAL PROBLEM
FUEL FILTER/PRESSURE REGULATOR DEFECTIVE (HIGH)
FUEL FILTER/PRESSURE REGULATOR DEFECTIVE (LOW)
FUEL PUMP CAPACITY (VOLUME) OUT OF SPECS
FUEL PUMP DEFECTIVE (LOW OUTPUT)
