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03 z71 issues help asap please

Discussion in 'GM Powertrain' started by CD82, Oct 11, 2012.

  1. CD82

    CD82 New Member

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    ok i have a 2003 z71 silverado its got the 5.3l in it with 4l603 transmission.
    ive been having issues for quite sometime now with it losing rpms and dying at ide speeds.
    such as when im comming to a stop light or sign or go to park in a parking lot.
    the tach will drop and the truck will fall on its nose an dye.

    ive done as suggested by mecahanics and the chevy house
    cleaned throttle body and MAF and the air intake filter.
    changed plugs and plug wires changed the fuel filter.

    and this problem still occurs ive heard it could be the drive by wire throttle body.
    or could be a leak in the intake gasket
    now ive priced a gasket and its about 70$ and i have a chiltons book.
    but is there a way i could test for this without a smoke machiene or ?

    could someone help with some issues here?
    #1
  2. the phantom

    the phantom New Member

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    Welcome to the club!! Is your check engine light on? If it is have the trouble code read and that may lead to your issue. If its not on then I would think that it would not be your intake gasket as a manifold absolute pressure (map) sensor should trigger the CEL because of inconsistant readings. Good luck and we hope to see some pics of your truck!!
    #2
  3. CD82

    CD82 New Member

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    check engine lite has been on since ive got the truck and only codes it shows are the o2 sensors.
    it has headers all people ive spoken to about that says theh eaders are prob why check engine lite is on.

    thats the only code it has ever showed

    hehe my truck is ugly has to many issues for pics kinda embarrased of it
    #3
  4. ChevyBoy2009

    ChevyBoy2009 New Member

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    Fuel pump??...my old 03 silverado had a fuel pump go out at 120k and when i took it out to replace it,it already had a junkyard fuel pump in it...
    #4
  5. CD82

    CD82 New Member

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    i seem to be getting 58lbs to the fuel rail from the pump
    #5
  6. TimTom64b

    TimTom64b New Member

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    I would guess the its not getting enough fuel at idle... Maybe MAF sensor, fuel filter or fuel pump.
    I'm sure others will chime in.

    And yes headers will cause lean codes to trigger on bank1 and 2... Mine did hense my purchase of the trinity and custom tune from diablew tune.
    #6
  7. Pikey

    Pikey Moderator

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    I had the same stalling issue with an 03 yukon xl. When I bought it, it would bog down and stall at lights. turned out to be a bad battery and alt
    Last edited: Oct 12, 2012
    #7
  8. CD82

    CD82 New Member

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    ive replaced the fuel filter checked hte pressure of the fuel pump appears ive got 58lbs to the rail.
    #8
  9. Pikey

    Pikey Moderator

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    I understand that, as you posted that information in a previous post. I was just stating that I had a 03 truck that did the exact same thing. It turned out to be the battery. If you know that you have bad 02 sensors then you need to fix that or the computer will give the wrong commands for fuel, spark advance and spark retard. The bad O2 sensors can destroy your MPG also. If you have duel exhaust and the sensors are not installed then you need to install o2 replicators.
    #9
  10. CD82

    CD82 New Member

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    my mpg is great actiualy 15 mpg in town i think that is decent

    i will get the alt and battery checked the battery seems to hold a very good charge
    from what the guage says in the dash but i have them chekced to make sure


    battery is less than a year of it it turns out to be that then i can get it replaced.
    #10
  11. Pikey

    Pikey Moderator

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    I just reread your original post, if you are thinking that it is an intake manifold gasket you can test it by spraying carb cleaner around the edges of it while the truck is running. if the RPMs increase then you found your issue.
    #11
  12. CD82

    CD82 New Member

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    hey thanks this is something else i can try im also going to be trying a soapy water solution.
    tomorrow like chiltons says to check vacum hoses for leaks
    #12
  13. dpeter

    dpeter New Member

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    You won't have any luck checking vacume lines with soap solution unless you can pressurize them somehow. As Pikey suggests, try some carb cleaner sprayed around the mating surfaces and hoses while running and you will get a change in RPM if there is a leak.
    #13
  14. CD82

    CD82 New Member

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    will throttle body cleaner work or does it have to be just carb cleaner?
    #14
  15. CD82

    CD82 New Member

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    well did the carb cleaner trick and no leaks while running.

    im at a loss here

    i was setting in the driveway gie it a lil gas let off the rpms drop
    and it died it does this more so when turning the wheels left or right!
    #15
  16. dpeter

    dpeter New Member

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    You had mentioned a drive by wire setup. is your engine drive by wire? Two things come to mind... first is the Idle Air Control may not be working correctly and second is the Exhaust Gas Recirculation valve may be stuck open. I am not familiar with the 03 and it may have both or neither. Are you able to start it back up Ok after it has died? Aside from a little load on the engine I can't imagine what steering iinput could affect.
    #16
  17. CD82

    CD82 New Member

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    it fires right up no problem and will idle real good yes it is drive by wire

    this is only occuring when im slowing down the rpms drop an will sometimes die
    or when im in a parking lot and go to turn the wheel it will die

    i can leave it in park rev it a bit turn the wheel one way or the other and it wil die
    #17

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