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  1. #11

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    You can buy a can a MAF sensor cleaner and try it. It is worth the $8.

    1995 Silverado 4x4
    6" BDS Suspension Lift-3" Body Lift-Add A Leaf in rear -Trailmaster SSV Shocks-Duel Steering Stabilizer Kit -AirAid Cold air intake-
    4.56 Gears with Detroit Auburn Locker-Pro-Comp Traction Bars with duel shocks-Aluminum Skid Plate Kit-38.5" x 16.5" Mickey Thompson Baja Claws-Constant Dropping fuel gauge

    2005 Yukon XL Jet Power Programmer, Bilstein Shocks, Bilstein rear springs, Helwig Anti-sway bars, EGR Window Visors, EGR Hood Shield, Denali Headlights, Headlight harness upgrade, GE NightHawk Bulbs, White Night Rear lighting system, Russell Braided SS brake lines, PowerStop Brake pads, PowerStop cross drilled and Slotted Rotors, http://www.gmtruckclub.com/forum/sho...5-GMC-Yukon-XL
    2002 Silverado ext cab 2wd (Sold)
    2003 Yukon XL (Totaled)

  2. #12

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    Quote Originally Posted by Pikey View Post
    You can buy a can a MAF sensor cleaner and try it. It is worth the $8.
    Yeah, I'll swing by the store tonight and hopefully that will clear it up and save me $$ for a new MAF

  3. #13

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    Coolant temp sensor is a more likely candidate if you aren't getting a check engine light. There are 2 of them. One for the gauge and one for the ECM. The one for the ECM is in the intake next to the thermostat housing.
    "It went together didn't it? Well then there has to be a way to take it apart!" - Me.

    Check out my image gallery HERE.



    "The true measure of a man is how he treats someone who can do him absolutely no good." ~Samuel Johnson (1709-1784)

  4. #14

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    Quote Originally Posted by moogvo View Post
    Coolant temp sensor is a more likely candidate if you aren't getting a check engine light. There are 2 of them. One for the gauge and one for the ECM. The one for the ECM is in the intake next to the thermostat housing.
    I do have a check engine light, or did, before today for the cats being bad. On constantly, just put on the new y pipe. Light was off but the engine was warm. If the light comes back tomorrow ill know its the MAF. The codes were for both banks running lean and multiple misfires detected. Shop cleared the codes, cleaning the MAF sensor tonight and ill know tomorrow morning if I need to drop cash on a new sensor, fingers crossed.

    - - - Updated - - -

    Quote Originally Posted by TimTom64b View Post
    Yes get the codes... This will verify. I am guessing lean as it would be rare for the two to be tripping otherwise. I have a feeling it will be lean on bank 1 and bank 2. This is what my sons truck did when is MAF failed.
    Hoping you're right but that its just dirty, not needing replacement

    - - - Updated - - -

    No dice, after cleaning the MAF sensor lastnight fired it up this morning and the check engine light came on, heard it misfire 2 or 3 times. The light turned off after the engine warmed up.

    P0170 bank 1 lean
    p0174 bank 2 lean
    p0300 random misfire detected

    looks like ill be spending a few bucks on a MAF sensor :(

  5. #15

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    Check out some of the site sponsors like AutoAnything. There prices are usually pretty good

    1995 Silverado 4x4
    6" BDS Suspension Lift-3" Body Lift-Add A Leaf in rear -Trailmaster SSV Shocks-Duel Steering Stabilizer Kit -AirAid Cold air intake-
    4.56 Gears with Detroit Auburn Locker-Pro-Comp Traction Bars with duel shocks-Aluminum Skid Plate Kit-38.5" x 16.5" Mickey Thompson Baja Claws-Constant Dropping fuel gauge

    2005 Yukon XL Jet Power Programmer, Bilstein Shocks, Bilstein rear springs, Helwig Anti-sway bars, EGR Window Visors, EGR Hood Shield, Denali Headlights, Headlight harness upgrade, GE NightHawk Bulbs, White Night Rear lighting system, Russell Braided SS brake lines, PowerStop Brake pads, PowerStop cross drilled and Slotted Rotors, http://www.gmtruckclub.com/forum/sho...5-GMC-Yukon-XL
    2002 Silverado ext cab 2wd (Sold)
    2003 Yukon XL (Totaled)

  6. #16

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    Quote Originally Posted by kinson33 View Post
    p0300 random misfire detected
    Now we have something to work with. Codes are the first thing that should be presented when anyone has a problem.

    The random misfire maybe the first area to look at. You talked about the sound of a misfire in the original post, but I didn't think you actually had a mis-fire (no code/flashing CEL, was discussed). As you appear to be aware, the misfire will destroy the cat(s). The misfire, along with the bad cats will cause a lot of fuel ratio problems. My advise is to fix the misfire and get new cats. Forget about chasing the lean bank 1 and 2 problem until you have fixed the known problems.

    Recheck the wires, are they connected in the correct firing order, are they properly seated on the plug and the connector?

    Did you buy a wire set that was terminated at both ends, or did you cut the wires and terminate them yourself?

    What brand of plugs did you use?
    Ray

    '09 Avalanche LTZ - Black
    '05 Envoy XL (sold)

  7. #17

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    Quote Originally Posted by RayVoy View Post
    Now we have something to work with. Codes are the first thing that should be presented when anyone has a problem.

    The random misfire maybe the first area to look at. You talked about the sound of a misfire in the original post, but I didn't think you actually had a mis-fire (no code/flashing CEL, was discussed). As you appear to be aware, the misfire will destroy the cat(s). The misfire, along with the bad cats will cause a lot of fuel ratio problems. My advise is to fix the misfire and get new cats. Forget about chasing the lean bank 1 and 2 problem until you have fixed the known problems.

    Recheck the wires, are they connected in the correct firing order, are they properly seated on the plug and the connector?

    Did you buy a wire set that was terminated at both ends, or did you cut the wires and terminate them yourself?

    What brand of plugs did you use?
    cant mess up the firing order, they're straight down... Msd wires and auto lite iridiums. Greased and all seated nicely. CEL was on the whole time but didn't get the codes until I got the new cats installed yesterday. Cel stayed off after that. Fired up again this morning, cel came back on then turned off after the engine warmed up a little (4 mins of running) which led me to believe its the MAF like someone mentioned since all symptoms go away after its warm and relying on the o2 sensors info

    - - - Updated - - -

    Also, if it were a plug or wire issue it would be running like crap even after it warmed up?

  8. #18

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    You need to understand that during open loop operation (initial running before engine heats up) that the ECM completely ignores all sensors and runs directly from per programmed fuel tables. Sensors cannot set a code until the system goes into closed loop mode unless they are completely missing or disconnected.

    You seem to be sold on the idea of the maf needing repaired. I don't think that is your issue. You can clean/replace it if you want, but at this point, it is just wasted effort until you fix the misfire. Fix the known first, then worry about residual issues afterwards.
    "It went together didn't it? Well then there has to be a way to take it apart!" - Me.

    Check out my image gallery HERE.



    "The true measure of a man is how he treats someone who can do him absolutely no good." ~Samuel Johnson (1709-1784)

  9. #19

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    Quote Originally Posted by moogvo View Post
    You need to understand that during open loop operation (initial running before engine heats up) that the ECM completely ignores all sensors and runs directly from per programmed fuel tables. Sensors cannot set a code until the system goes into closed loop mode unless they are completely missing or disconnected.

    You seem to be sold on the idea of the maf needing repaired. I don't think that is your issue. You can clean/replace it if you want, but at this point, it is just wasted effort until you fix the misfire. Fix the known first, then worry about residual issues afterwards.
    plugs went in no issues, wires clicked in place, they were already terminated, all wires correspond to correct plugs. What would cause misfire on start up but then run normal at operating temp? That's why I'm stuck on an air issue

  10. #20

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    Allot of things can cause the misfire... Assume your rotor and cap have been replaced? A beginning to fail ignition control module... Pretty much functions as a condensed in the newer ignition systems can cause a misfire too. A MAF life is rated at around 50k miles... After that they start to degrade. MAF sensor when it really fails the will run like crap no matter the temp... And RPM. With my boys truck we replace all the o2 sensors, temp sensor, cap rotor, wires and plugs... I was at wits end... And then changed the MAF sensor as a last resort before taking it to a shop... Walla... All was good.
    2009 Chevy Silverado 2500HDLT 6.0L w/ Towing Package, Dick Cepek GM8 Rims, Dick Cepek FC II 33X11.50R17,RKSport Ram-Air Hood(Functional), Lazer Lite Aluminum Tonneau Cover, Road Armor Stealth Bumper, PIAA Lighting, Diablo Trinity Tuner, Diablew Custom Tune, BullyDog Cold Air Intake, American Racing Headers w/highflow cats, Corsa Performance Sport Exhaust, Custom Striping, Black Bowties front and rear, Fuel Grille Inserts, Recon Headlights, Readylift Shocks, Readylift Upper Contol Arms, 2" Blocks in the Rear..

    Future Plans: HD Tie Rods, Under hood upgrades, Crower Camshaft and possibly electric fans.

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