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Any GM techs, 2003 6.0 miss fire?

Discussion in 'Shooting Related Threads' started by maclellan1911, Jan 15, 2009.

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  1. maclellan1911

    maclellan1911 TS Member

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    had a 2003 3500 van 6.0 48K. dead miss on cyl. 2 and so so miss on cyl 6. plugs good swapped coils, wires around to see if miss moves. EVAP smoke leak detector showed leak at intake. Replaced intake with updated green gasket. Now the fun. Dead miss on 2 is gone along with 6. BUT NOW at no uncertain time I get drop out and miss fires at idle in pairs??? 8 & 7 , 1 & 4 , and a few times 2 & 6 . fuel preasure good, fuel sample looks ok. Even swapped around the injectors? Any tips????????
     
  2. ec90t

    ec90t Guest

    I know you didn't touch the crank sensor, but that's where I'd start.

    ec90t
     
  3. emm2

    emm2 Member

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    Did you smoke test it after you did the intake? Check for signs of fuel in the vacuum hose going to the fuel pressure regulator. Did you look at the fuel injectors when you had them off, they are common to mud up and not flow correctly. If you have a scan tool are the front oxygen sensors sweeping from near 0 volts to near 1 volt? You can also unplug the front O2 sensors and see if the miss goes away. The O2 sensors usually will cause 1 bank to miss but I have seen stranger things. Does the miss go away at higher rpm's? If so perform crankshaft variation relearn. Check all computer grounds for loose or corroded connections.
     
  4. maclellan1911

    maclellan1911 TS Member

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    no crud on top of injectors that we could see, did check the grounds. We learned to day this guy has been all over with this problem. We found out from a GM tech who knows this van. To date it has had CATs, O2s, computer, crank and cam sensor replaced under warrenty? After he mentioned this, I did notice the cam sensor looked kinda fresh. 48k clean truck????? We called our GM go to guy. He brought down his factory scan tool, found nothing strange. When he came and saw the van, "I know this van"! Ended there. The dead miss is gone! engine light no longer comes on. Customer is not to happy, but the light has stayed off since the gasket replacement. That was his major concern.
     
  5. dsid01

    dsid01 TS Member

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    Have you checked websites like Identifix or IATN they are usually very helpful
     
  6. maclellan1911

    maclellan1911 TS Member

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    The customer is glad to have the dead miss gone, After confronting him about his past problems he did FINALLY tell us the whole story. Aparently the van has never ran right. Dead miss is gone, light stays off. He is on his way to GM again for cleaning of injectors and some sort of reprogram? Apparently he has a friend with same van, the ejector cleaning and reprogram helped??
     
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