Quick diagnostic emissions question

Discussion in 'The BS Topic' started by 327 BlackBird, Jan 22, 2011.

  1. 327 BlackBird

    327 BlackBird Veteran Member

    Short story.

    My 2005 avalanche has recently began multiple misfiring at various times. Only at idle, never at speed. Shut the truck off. Start it up. Usually clears the problem up for a week or more.

    Throws random misfire code. Also has thrown a 02 sensor fault code twice.
    It has had a tuneup in the last month. Everything else works and checks out fine.

    Coming home from generous motors tonight. Ran fine. But ate a ton of gas. Filled up before I started my last leg home. Ran like crap, I knew it was misfiring, but it also misfired up to speed until I hit about 80 then smoothed out.

    Idiot light came on and actually stayed on. Not just flash at me and dissapear.

    Scanned it when I got home. 3 oxygen sensors have thrown codes. 2 are GM specific. Also a random misfire code. Exhaust smells like crap. I know the cat is good still for the time being as it smells fine when the truck is my acting up.

    With 250,000 km on the odometer. I am thinking they are original and they looked original when I installed my flowtech mufflers. I was gonna replace all 4 this weekend and see what it does. I don't have access to my genesis scanner for a few days so I cannot check the voltage and ohm and milliamp readings.

    But for 02 codes to have been thrown, twice before and now 3 out of 4 tossing codes tonight, what do you think?
  2. That it probably isnt the O2 sensors.

    But at all I dont have clue, sorry.

    I heard this kind of problem several times in the las few months, although here in Germany, but for sake cant remember what the problem was.
  3. MrAzzhat2U

    MrAzzhat2U Veteran Member Lifetime Gold Member

    Jan 31, 2000
    Lewes DE
    This could be your problem!

    Bulletin No.: 03-06-04-030G

    Date: April 22, 2009

    Various Driveability Symptoms Due to Clogged Fuel Injectors, MIL/SES DTCs P0171, P0172, P0174, P0300, P1174, P1175 (Clean Fuel Injectors and/or Perform Injector Test With AFIT CH-47976)

    2005-2009 GM Passenger Cars and Light Duty Trucks
    2005-2009 HUMMER H2
    2006-2009 HUMMER H3
    2005-2009 Saab 9-7X

    Equipped with Engine RPOs listed in the Table above and MULTEC(R) 2 Fuel Injectors

    GM does not support cleaning injectors on any engines that are not listed in this bulletin. Engines other than the ones listed in this bulletin that diagnosis indicates having restricted injectors should have those injectors replaced.

    This bulletin is being revised to update the model year to 2009 and to provide applicable engine RPO table. Please discard Corporate Bulletin Number 03-06-04-030F (Section 06 - Engine/Propulsion System).


    Some customers may comment on any of the following various driveability symptoms:

    - Extended Crank Time

    - Hard to Start

    - MIL/SES Illuminated with DTCs

    - Hesitation

    - Lack of Power

    - Surge or Chuggle

    - Rough Idle

    - Light or Intermittent Misfire


    Due to various factors, the fuel injectors may become restricted. Extensive testing has demonstrated that fuel related issues are the cause of clogged injectors. At this point, no specific fuel, fuel constituent, or engine condition has been identified as causing the restriction. The restriction causes the engine to operate at a lean air fuel ratio. This may either trigger the MIL to illuminate or the engine to develop various driveability symptoms.


    Fuel injector restrictions, deposits can be cleaned on the vehicle using the following procedure. Under NO circumstances should this procedure be modified, changed or shortened. As a long term solution, and to prevent reoccurrence, customers should be encouraged to use Top Tier Detergent Gasoline. For further information on Top Tier detergent gasoline and fuel retailers, please refer to the following Corporate Bulletin Numbers:

    - 04-06-04-047G (U.S. Only)
    - 05-06-04-022D (Canada ONLY)

    GM UPPER ENGINE AND FUEL INJECTOR CLEANER is the only injector cleaning agent approved for use with General Motors fuel system components. Other injector cleaners may cause damage to plastics, plated metals or bearings. General Motors has completed extensive laboratory testing of GM Upper Engine and Fuel Injector Cleaner, and can assure its compatibility with General Motors fuel system components, as long as the cleaning procedure is followed correctly.

    Injector Cleaning Procedure

    The following tools, or their equivalent, are required:

    - CH-47976 Active Fuel Injector Tester (AFIT)
    - J 35800-A Fuel Injector Cleaner
    - J 37287 Fuel Line Shut-off Adapter
    - J 42964 Fuel Line Shut-off Adapter
    - J 42873 Fuel Line Shut-off Adapter
    - * One bottle of GM Upper Engine and Fuel Injector Cleaner, P/N 88861802 (in Canada, P/N 88861804)
    - * One bottle of GM Fuel System Treatment Plus, P/N 88861011 (in Canada, P/N 88861012)

    Active Fuel Injector Tester (AFIT- CH-47976)

    Some dealers may not have an Active Fuel Injector Tester (AFIT- CH-47976). Dealers can contact to order an AFIT- CH-47976. Dealers still can test the fuel injectors without an AFIT. Refer to Fuel Injector Diagnosis (w/ J 39021 or Tech 2(R)) in SI.

    As mentioned in the AFIT User Guide, vehicles that are not listed in the AFIT menu can still be tested with the AFIT. Depending on the model, it may be possible to enter the previous model year and proceed with testing using the DLC connection. If this is not possible on the model that you are working on, it will be necessary to use the direct connection method outlined in the AFIT User Guide (See Pages 17-31).

    General Motors recommends that the Active Fuel Injector Tester (AFIT) be used in testing fuel injectors. If the SI diagnostics do not isolate a cause for this concern, use the Active Fuel Injector Tester (AFIT - CH-47976) to perform an "Injector Test" as outlined in the AFIT User Guide.

    The AFIT "Injector Test" measures the flow characteristics of all fuel injectors, which is more precise when compared with the standard Tech 2(R) fuel injector balance test. As a result, the AFIT is more likely to isolate the cause of a P1174 DTC (for example: if it is being caused by a fuel injector concern).

    The CH-47976 (Active Fuel Injector Tester - AFIT) can also be used to measure fuel pressure and fuel system leak down. Also, as mentioned in the P1174 SI diagnosis, if the misfire current counters or misfire graph indicate any misfires, it may be an indicator of the cylinder that is causing the concern. Refer to Fuel Injector Diagnosis (w/CH-47976) in SI for additional instructions.

    Training (U.S.)
  4. MrAzzhat2U

    MrAzzhat2U Veteran Member Lifetime Gold Member

    Jan 31, 2000
    Lewes DE
    Or this!
    Bulletin No.: 06-06-04-046

    Date: September 12, 2006


    Information on Engine Misfire MIL/SES Light Illuminated or Flashing DTC P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308, P0420 or P0430

    1999-2007 Cadillac, Chevrolet, GMC Full-Size Pickup and/or Utility Trucks

    with 4.8L, 5.3L, 5.7L, 6.0L or 6.2L VORTEC GEN III, GEN IV, V-8 Engine (VINs V, C, T, Z, B, 3, M, 0, J, R, U, N, Y, K, 8 - RPOs LR4, LY2, LM7, L59, L33, LC9, LH6, LMG, LY5, L31, LQ4, LQ9, L76, LY6, L92)

    with Active Fuel Management(TM) and E85 Flex Fuel

    If you encounter vehicles that exhibit the above conditions, refer to SI for the appropriate DTC(s) set. If no trouble is found, the cause may be due to an ECM ground terminal that has corroded with rust over time. Inspect the main engine wiring harness ground terminal (G103) for this condition.

    The wire terminal (G103) attaches either to the front or to the rear of the right side cylinder head, depending on the model year of the Full Size Pickup and/or Utility Trucks. If the ECM ground terminal has been found to be corroded, then follow the service procedure outlined in this bulletin to correct the corrosion issue.

    Remove either the nut or bolt securing the main engine wiring harness ground terminal (G103) to the right cylinder head. Refer to the above illustration to determine where the ground is located on the vehicle (1).

    Remove all rust from the ground terminal, the cylinder head and the retaining nut or bolt.

    Position the main engine wiring harness ground terminal and install the nut or bolt.


    Tighten the retaining nut or bolt to 16 N.m (12 lb ft).

    Apply some type of electrical moisture sealant to protect the harness terminal from further corrosion.
  5. 327 BlackBird

    327 BlackBird Veteran Member

    That injector cleaning doesent appear to be a recall. Crap, I don't want to bring it into the dealer for a terraclean. And I don't have active fuel management.

    These are the codes I am getting.

    P0300 multiple random misfire
    P1133. H02s insufficient switching sensor 1 or bank 1 sensor 1

    P1153. H02s insufficient switching bank 2 sensor 1

    P0138. 02 circuit high voltage bank 1 sensor 2

    P0158. 02 circuit high voltage bank 2 sensor 2

    P0171 system too lean bank 1

    P0174 system too lean bank 2
    Last edited: Jan 22, 2011
  6. Knuckle Dragger

    Knuckle Dragger Administrator Staff Member Lifetime Gold Member

    Nov 2, 2002
    Waddell AZ
    When a vehicle miss-fires it put unburned fuel and oxygen into the exhaust, right? Makes sense if it isn't burring it it has to go somewhere. With me? The o2 sensor senses o2, not fuel. So, when dealing with a misfire you have to throw out all o2 related codes, ignore fuel trim for the most part and figure out the miss-fire before you move on. Chasing ghost codes gets expensive.

    Any engine noise? We have been seeing a good number of valve train related parts failures through out the mileage of the fleet.
  7. 327 BlackBird

    327 BlackBird Veteran Member

    I can't see all 4 going at the same time. They cost $120 a peice my cost! Time to dig.
  8. 327 BlackBird

    327 BlackBird Veteran Member

    No engine noise at all. Runs like a champ for the most Part when it's not misfiring. All this started when I put in the NGk plugs. I was going to put back in the ac delco plugs that were in it as they don't look to bad. Worth a shot.
  9. MrAzzhat2U

    MrAzzhat2U Veteran Member Lifetime Gold Member

    Jan 31, 2000
    Lewes DE
    You failed to mention this tidbit of info!Did you change the wires too?They are usually hard to get off and can pull apart inside the casing.I'd go back to square 1 and throw a can of Seafoam in it when you are done!You don't want to keep running it like that or you will be putting cats on it!
  10. ProStreet383

    ProStreet383 Veteran Member

    May 23, 2007

    You forgot to mention it started after you did the tuneup. That is an awful strange coincidence don't you think? What plug wires did you use? First put the stock plug wires back on and if problem still there then put the stock ac plugs back in. I bet money it is one of those two things causing the issue and most likely bad plug wire because most LSX guys run the NGK TR55 with fantastic results including myself. I have a new set sitting here actually.

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