2005 z71 missfire

Discussion in '4X4 Truck Talk and Repairs' started by biermann83, Jan 3, 2009.

  1. biermann83

    biermann83 New Member

    I have a 2005 z71 that recently went in for a coolant leak and rough idle. They found the water pump was leaking and replaced the o2 censor. After that it was still rough. so they replaced the intake gaskets and checked all the injectors but they were good. The motor is misfiring on all four cylinders on the drivers side and it spits out a black watery mix from the exhaust and smells like rotten eggs. so any ideas would be appreciated.
  2. Creteus

    Creteus New Member

    Loganville, GA
    black water is normal. You probably have alot of carbon in the exhaust because of the misfireing. The rotten egg smell is normally a bad catalytic converter. I'm not familure with the 05s as how the ignition goes but if its misfiring on one side and if it has coil packs, I'd say one is bad. There should be a code in the computer saying whats going on.

  3. smokey869

    smokey869 New Member

    is it missing just at idle or while driving also ?, could be a number of things, i would check the fuel pressure regulator, just pull the vacume hose off and check for fuel there, there should not be any at all, even if its damp start the vehicle with the vac hose off and see if you get any fuel there, if not its down to basics, spark check the coils and check the injectors again, also did they replace the o2 sensor on that side that is missing? ive had a frt o2 sensor making the engine run way too rich, you need someone with a good scanner and the know how to check this
  4. cantstopgrandma

    cantstopgrandma New Member

    If its anything like dad's '99, each cylinder has its own coil pack, so i would say its not that (if it is indeed misfiring on all 4 cylinders). Dont those engines pick up their firing order from a sensor on the crank (i think they refer to it as optispark)? I know one person with a buick roadmaster, when his water pump was leaking, it was dripping coolant onto the optispark unit and causing a misfire. Its worth checking anyways.
  5. drpepper

    drpepper New Member

    hmmm got all cylinders misfiring on one bank... no wonder you had an o2 code.
    You need to fire that shop and suggest they find something else to do for a living- take it to someone who knows what their doing instead of throwing parts at it and keeping their fingers crossed.... what a shame, I hope they didnt charge you anything for parts or labor.

    These type of drivability problems (misses) are ALWAYS a simple diag.