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goodwrench9124
goodwrench9124, ASE Certified Technician
Category: Chevy
Satisfied Customers: 3431
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i got code p0171 and p0174 on my 2001 chevy suburban. what ...

Resolved Question:

i got code p0171 and p0174 on my 2001 chevy suburban. what can i do to fix it.
Submitted: 6 years ago.
Category: Chevy
Expert:  goodwrench9124 replied 6 years ago.

Hello, and welcome to JA!!! codes PO171 and PO174 indicates both banks are running lean. the two most common problems for these codes are a weak fuel pump, or a intake gasket leaking vac. if the vehicle starts ok, the normally the fuel pump is ok. more than likely the intake gasket will need to be replaced. let me now if you need any further info on this concern.

: Cold Engine Idle Misfire Or DTCs P0171 P0174 - keywords 4.8 5.3 6.0 air cold crack hesitate idle intermittent internal intake leak lean misfire miss P0171 P0174 P0300 power rough surge vacuum

Subject:Cold Engine Idle Misfire or DTCs P0171 P0174

Models:2002-2005 Cadillac Escalade
1999-2005 Chevrolet Avalanche, Express, Silverado, Suburban, Tahoe, Trailblazer
1999-2005 GMC Savana, Sierra, Yukon
2003-2005 Hummer H2

 


 


 

 

Condition/Concern:

99 through 05 GEN III truck engines may experience any of the following:

A cold rough idle that diminishes as the engine warms up.

Possible DTCS P0171, P0174, or P0300.

Random misfires at idle.

Recommendation/Instructions:

The intake gasket seals may be leaking around the intake ports, causing a lean condition. The intake gasket seals may leak around the bottom side of the port, making it a challenge to detect the vacuum leak. The technician may also notice lower than normal MAF readings if the intake seals are leaking.

If leaking intake gasket seals are found, replace the intake gaskets. During the repair be sure to use the current GMSPO part number for replacement intake gaskets. The current GMSPO part number for intake gaskets will have a teal green intake gasket seal. The old version of the intake gaskets were orange in color. Use only the teal green colored gaskets for a repair.

 

Customer: replied 6 years ago.
Reply to goodwrench9124's Post: is this a big job to do. or should i take it to a shop. i know my way around the engine a little bit.
Expert:  goodwrench9124 replied 6 years ago.

fairly easy repair, if you have some mechanical skills, should be able to handle. takes a couple of hours to do.

 

Object Number: 492770  Size: SH Object Number: 642285  Size: SH

Customer: replied 6 years ago.
thank you very much, also i read it could be tha vac hose. i did get the code p0300 also when i got the others codes. do you have a daigram how to change the intake gasket or a web site i can go to get it
Expert:  goodwrench9124 replied 6 years ago.

here are the instructions.

Intake Manifold Replacement

Removal Procedure

Important: The intake manifold, throttle body, fuel rail, and injectors may be removed as an assembly. If not servicing the individual components, remove the manifold as a complete assembly.


    Object Number: 600833  Size: SH

  1. Remove the engine sight shield and retainer.
  2. Relieve the fuel system pressure.
  3. Disconnect the cruise control cable from the throttle blade stud.
  4. Remove the cruise control cable from the bracket.
    Object Number: 389031  Size: SH

  5. Remove the accelerator control cable from the throttle blade.
  6. Remove the accelerator control cable from the bracket.
    Object Number: 679597  Size: SH

  7. Disconnect the following electrical connectors:
    Main ignition coil harness (2).
    Fuel injectors (3)
  8. Disconnect the wiring harness clips (1) from the fuel rail.
    Object Number: 679598  Size: SH

  9. Disconnect the following electrical connectors:
    Main ignition coil harness (1)
    Fuel injectors (3)
    Exhaust gas recirculation (EGR) valve (4)
  10. Disconnect the harness clips (2) from the fuel rail.
    Object Number: 679510  Size: SH

  11. Disconnect the following electrical connectors:
    Manifold absolute pressure (MAP) sensor (1)
    Knock sensor (2)
  12. Remove the knock sensor harness electrical connector from the intake manifold.
  13. Set the electrical harness aside.
    Object Number: 389028  Size: SH

  14. Disconnect the following electrical connectors:
    Throttle position (TP) sensor, if equipped
    Electronic throttle control (ETC) motor, if equipped
    Idle air control (IAC) valve

    Object Number: 663672  Size: SH

  15. Disconnect the following electrical connectors:
    Purge solenoid (1)
    Generator (3)
  16. Remove the wiring harness bracket nut.
  17. Remove the harness bracket from the stud.
  18. Reposition the engine wiring harness.
    Object Number: 220621  Size: SH

  19. Reposition the coolant air bleed hose at the throttle body.
  20. Remove the coolant air bleed hose from the throttle body.
    Object Number: 659465  Size: SH

  21. Reposition the radiator vent inlet hose clamp at the throttle body.
  22. Remove the radiator vent inlet hose from the throttle body.
    Object Number: 647795  Size: SH

  23. Remove the positive crankcase ventilation (PCV) hose from the throttle body and rocker arm cover.
    Object Number: 647793  Size: SH

  24. Remove the PCV hose (with valve) from the intake manifold and rocker arm cover.
    Object Number: 679527  Size: SH

  25. Remove the following EGR pipe bolts:
    Intake manifold (1)
    Cylinder head (2)
    Exhaust manifold (3)
  26. Remove the EGR pipe (with valve).
  27. Remove the EGR pipe gasket from the exhaust manifold.
    Object Number: 382483  Size: SH

  28. If equipped, remove the vacuum brake booster hose from the rear of the intake manifold.
    Object Number: 372717  Size: SH

  29. Remove the evaporative emission (EVAP) purge solenoid vent tube by performing the following:
    29.1. Remove the EVAP tube end (2) from the solenoid (1).
    29.2. Squeeze the EVAP pipe quick connect fitting (3) retainer together.
    29.3. Remove the EVAP tube end (3) from the vapor pipe.
  30. Disconnect the fuel line quick connect fittings. Object Number: 642285  Size: SH

  31. Remove the intake manifold bolts.
  32. Remove the intake manifold.
    Object Number: 492770  Size: SH

  33. Remove the intake manifold gaskets (1) from the intake manifold.
  34. Discard the old intake manifold gaskets.
  35. Clean the gasket surfaces of the EGR pipe and the exhaust manifold.
  36. If replacement of the intake manifold is required, remove the following components:
    Throttle body.
    Fuel rail and injectors.

    Object Number: 260159  Size: SH

  37. If replacement of the intake manifold is required, remove the MAP sensor (1).
    Object Number: 492765  Size: SH

  38. If replacement of the intake manifold is required, remove the accelerator control cable bracket bolts (1) and bracket (2).
    Object Number: 389993  Size: SH

  39. If replacement of the intake manifold is required, remove the EVAP solenoid bolt (2), solenoid (3) and isolator (1).
goodwrench9124, ASE Certified Technician
Category: Chevy
Satisfied Customers: 3431
Experience: Ase Master Certified, GM Master Certified Tech. Awarded GM Top performer, Hybrid certified
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