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Hunting idle

Discussion in 'VR - VS Holden Commodore (1993 - 1997)' started by Rice car, Oct 29, 2018.

  1. Rice car

    Rice car New Member

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    Hey guys

    Some info on the car in question:

    95 VS commodore, manual, l67 conversion + mods.

    The issue:

    Just wondering if anyone would have any idea on where or what to look at that would cause my car to hunt at idle. It is probably the reason my car also has a DTC 76.
    I've searched for vacuum leaks but haven't found anything. I do plan on replacing every vacuum line anyway, so if anyone has a diagram for an l67 or even knows what size hoses are needed, that would be great.

    Also, the car has a (what feels like) misfire when coasting at around 1500rpm, in any gear.

    So far I've replaced the dfi module, CAS, o2 sensors, purge solenoid, IAC valve, PCV.

    I've checked the spark plugs and leads (with a multimeter), injectors all work.

    Not sure where else to go. Just need a little bit of guidance, I've searched a fair bit and I've fixed what I thought it could be, short of pulling the motor apart and replacing gaskets. I am looking at doing compression testing through the week and probably buy a diagnostics cable to see if I can get anymore info.
     
  2. BottleFedVS

    BottleFedVS Member

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    Try replacing your coils or crank angle sensor.
    DTC 76 - Air/Fuel ratio variation between left and right banks
    This may be a false code thrown up because of the miss. However you may also want to check that both oxygen sensors are ok and in reasonable condition.
    I hope that helps.
     
  3. losh1971

    losh1971 Well-Known Member

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    Try cleaning the MAF
     
  4. Deuce

    Deuce Super Stock

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    Throttle blade manual stop adjusted correctly for proper IAC steps?
    This can effect hunting if you have been messing with it.
    If it used to go fine and you've never touched thia, DO NOT TOUCH IT NOW. Or you'll create more issues for later
     
  5. Rice car

    Rice car New Member

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    Already replaced the crank angle sensor and o2 sensors. I will look at buying some now coil packs because I have read that they can still be faulty even If tested ok (with a multimeter).

    have done so, no change

    I haven't touched it, but I can't say if the previous owners haven't. It's been doing it on and off since I got it. But now it seems to do it every time i stop (lights/signs/ect)
     
  6. Rice car

    Rice car New Member

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    Im now leaning towards lack of tune. It has basically been rebuilt with modified parts; cam, lifters, rockers, flat top piston (the main reason I feel the tune may be be non-existent), bigger injectors, fuel pump, smaller pully, pushrods, valves springs, exhaust, ect.

    Im probably better off putting in another motor and rebuilding this one, but I won't have time to for a few months.

    But I'm open to any other ideas that people may have in the meantime that I could check in case it has been tuned.
     
  7. mikman42

    mikman42 New Member

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    fuel pump could be dying
     
  8. Rice car

    Rice car New Member

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    Would it be intermittent though?
     

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