Tahoe error code DTC 0174 but no 0171

RFKCO

MEMBER
CHEVROLET TAHOE

2003 Tahoe, 55K miles, auto, 5.3L.
Rough idle when cold. Smother idle once fully warmed up. Acceleration seems normal. Check engine light - DTC 0174 - system too lean bank 2. Check engine light went off for a couple of days. Check engine light - DTC 0174 came back on. Error codes reset, check engine light off with reset, added bottle of fuel injector cleaner to gas tank. All this has happened in less than 200 miles. Air temperature in the 20's - 50's F. Only DTC 0174, no 0171 code. Do I have a bad injector on side 2?

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Update 12/02/2007 - thanks for all the help. The local Chevy dealer diagnosed the problem as a leaking intake manifold gasket. Cost was $500 to replace the gasket.

Ron

4 Replies

MERLIN2021

MECHANIC
17,250 POSTS

Look for vacuum leaks, if none found. The things to check, electronic coolant temp sensor, and intake air temp sensor.

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Friday, November 23rd, 2007 AT 12:32 PM

RASMATAZ

MECHANIC
75,992 POSTS

PO174 A lean fuel condition can be caused by:

* Low fuel pressure due to a weak pump or leaky fuel pressure regulator. (Use a fuel pressure gauge to check fuel pressure at idle)

* Dirty fuel injectors. (Try cleaning the injectors)

* Vacuum leaks at the intake manifold, vacuum hose connections or throttle body. (Use a vacuum gauge to check for low intake vacuum)

* Leaky EGR valve. (Check operation of EGR valve)

* Leaky PCV Valve or hose. (Check valve and hose connections)

* Dirty or defective Mass Airflow Sensor (MAF). (Try cleaning the MAF sensor wires or filament with aerosol electronics cleaner. Do NOT use anything else to clean the sensor, and do not touch the sensor wires)