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Truck running rough.Need help

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by bckinblk, Jun 14, 2003.

  1. bckinblk

    bckinblk 1/2 ton status

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    Today after putting the k-5 back together I started my truck (1988 k-5 5.7 tbi) It idled really rough So I took it for a cruise and it smoothed out .I shut it down for 5 minutes and I restarted it and It idled rough again .The truck sat for about 2 weeks and always ran good before .The only thing I could think of is I added some prolong to it before it sat .Could that've somehow messed it up ?? This is a break down of all the parts I changed on the engine last year Plugs -wires-cap-rotor-idle air control-coolant sensor-map-o2 It is not throwing any codes ..................Any suggestions?? /forums/images/graemlins/confused.gif
     
  2. Confedneck

    Confedneck 3/4 ton status

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    sounds like a pcm relearn, start it up and let it idle in park with all accessories off for about 5 minutes
    shut it off for 5 minutes, start it back up, see how it is
     
  3. bckinblk

    bckinblk 1/2 ton status

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    Ok I just tried it .It did improve a little but it still seems to have a stumble to it and the whole truck shakes .I will try to pull the plugs out to see if one is fouled .I am totally confused It just figures that I got it all back together and now I got a new problem WHY WHY..thanks for the advise.... /forums/images/graemlins/thumb.gif
     
  4. Confedneck

    Confedneck 3/4 ton status

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    try letting it idle, and pull one plug wire at a time, see if it changes the idle any, if you end up with one that doesnt change things, figure it out from there
     
  5. MousePowrd

    MousePowrd 1/2 ton status

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    [ QUOTE ]
    Today after putting the k-5 back together

    [/ QUOTE ]


    What do you mean "put it together"? What did you take off?
     
  6. bckinblk

    bckinblk 1/2 ton status

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    I put in a steering brace .Drag link and tranny mount .I doubt that has anything to do with it..It just started running rough at startup It runs smoother when warm but seems to sputter throughout the rpms ???I checked egr vac --good .checked wires-plugs-cap-.good.It is running very rich .Exhaust smells bad..??.Anyone... /forums/images/graemlins/confused.gif
     
  7. Confedneck

    Confedneck 3/4 ton status

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    smells bad? like what? rotten eggs? maybe the cat has gone south causing o2 sensor problems?
     
  8. bckinblk

    bckinblk 1/2 ton status

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    It smells like the gas is'nt burning all the way (very rich smell)I also noticed that I have an exhaust leak on the o2 side manifold. Could this cause what I am describing?? Is there a way to test the 02 sensor?? I am going crazy racking my brain trying to find this problem .Anyone out there have or had what I am describing ?? Please help..I will try a new fuel filter tonight ..although the pump and filter are fairly new...(confedneck) thanks for trying to help brother. /forums/images/graemlins/k5.gif /forums/images/graemlins/confused.gif
     
  9. Confedneck

    Confedneck 3/4 ton status

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    you saying you have an exhaust leak around the o2 sensor near the manifold? if so that would cause some wacky ass computer readings and probably a screwy idle...
     
  10. MousePowrd

    MousePowrd 1/2 ton status

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    A leak in the manifold before the O2 sensor will either lose heat and cause false readings, or introduce air causing the O2 to read lean. Fix the leak and replace the sensor (should be pretty cheap) and see if it helps. Just replacing the sensor is a waste of time without fixing the leak also
     
  11. bckinblk

    bckinblk 1/2 ton status

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    I found that it is leaking at the collector o ring.One of the 3 studs broke off leaving a small gap.So now I am looking for a used exhaust manifold .The leak is after the o2 would that still send funked up readings??thanks again
     
  12. MousePowrd

    MousePowrd 1/2 ton status

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    No, after the sensor is a different story. Did the problems all of a sudden start after you messed with the steering, or was it gradual?
    Even though you werent messing with the engine you could have knocked something off, like a wire or the vacuum line to the charcoal canister, or something.
     
  13. bckinblk

    bckinblk 1/2 ton status

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    I had the truck on stands put in a new t-case mount and brace and draglink .When I started it up I noticed a shimmer in the idle .And it's just getting worse .I added some prolong in it before I parked it .Today I put a new fuel filter and still the same .I will pull the IAC next for a cleaning. Any more suggestions??
     
  14. dheavychevy38

    dheavychevy38 1/2 ton status Premium Member

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    check your vaccum lines my 88 started burning gas and running rough found out it was the line to the map sensor it was dry rotten give them a try
     
  15. bckinblk

    bckinblk 1/2 ton status

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    I pulled out the IAC and sprayed it down with cleaner .When I put it back in the truck ran much better but still has a sputter .Could the IAC be bad??
     
  16. BlazerGuy

    BlazerGuy 3/4 ton status

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    If one of the studs broke off just put a new one in(you can get them from any good parts store, make sure you get the ones with the springs), you don't need to get a whole new manifold... /forums/images/graemlins/deal.gif
     
  17. Confedneck

    Confedneck 3/4 ton status

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    IAC could be bad, its a possibility... why not replace it if it hasnt ever been replaced...
     
  18. bckinblk

    bckinblk 1/2 ton status

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    I bought the IAC last year..Trying to find my reciept.. Anyway is there a way to test it..When I pulled it it was gunked up pretty bad ..Since I cleaned it the truck runs better but still not right. Thanks all for the help /forums/images/graemlins/thumb.gif /forums/images/graemlins/k5.gif
     

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