s10 sputters, runs like ****.

Discussion in 'Chevy Truck Forum' started by joshua.grimes, Aug 31, 2009.

  1. joshua.grimes

    joshua.grimes Member

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    I have a 92 s10 with the tbi 4.3. It starts, idles, cruises around the yard just fine. It has plenty of power at low rpm's/speed. As soon as I get it on the road, it starts to act like a powerless slob. Has a hard time getting over 30 mph.
    If I go down a long enough hill I can get it up to 60, and it will hold speed over flat ground, but will not go up hills.
    I think either my fuel pump or the strainer is clogged. I changed my fuel filter and it helped a little bit but not much. It also has newer plugs and wires, and a new cap and rotor.
    I was wondering if anyone has any insight as to what it could be. It is not legal right now, so I cant just drive up to autozone to have the codes read. I read something about a engine temp sensor, and maybe the throttle position sensor. I would rather not buy a $260 fuel pump if I done have to. I only payed $200 for the truck.
     
  2. bradrhale

    bradrhale Senior Member

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  3. Case 7230

    Case 7230 Senior Member

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    Check for trouble codes as suggested and check for restricted exhaust flow.
     
  4. joshua.grimes

    joshua.grimes Member

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    code 12

    I did the jumper thing, and it came up with code 12, flash, pause, flash flash. there is no listing on the 92-93 tbi page. What is code 12?
    not much of an exhaust to restrict. hollowed out cat, not much muffler.
     
  5. joshua.grimes

    joshua.grimes Member

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    throttle position sensor.

    I checked it out more.The motor revs nicely up to about 1/2 to 3/4 throttle, then it starts its sputtering.

    I unplugged the throttle position sensor, revved the motor a couple of times, it of course sputtered. I plugged the sensor back in and it revvs up pretty good. there is no corrosion on the plug or the sensor. is this a sign that the sensor is going bad?
    The egr valve moves freely, I dont know if it is holding vacuum, I didnt check.
     
  6. BernieB

    BernieB Senior Member

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    Sounds to me like your distributor isn't advancing. And 12 is IIRC, the "OK" code
     
  7. joshua.grimes

    joshua.grimes Member

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    I checked the timing first thing, thats what I thought too. Timing advances beautifully, with no issues. It idles very nicely, and revs up to part throttle nicely too. When the throttle hits a certain point the thing stumbles, stops revving, and will sometimes pop out the throttle body. As soon as I let go of the throttle it returns to idleing beautifully.
     
  8. BernieB

    BernieB Senior Member

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    Popping back through the TBI is usually either a timing issue or valve problems. My money is on timing, even though you've checked it. I've not worked on a 4.3 in more years than I want to admit, so I'm not sure if it uses a belt or a chain, but I'm thinking you skipped a tooth.
     
  9. BernieB

    BernieB Senior Member

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    One other possibility... Crossfiring due to bad wires or carbon tracks in the cap. Try goosing it a little at night, with no lights, and see if you spot any arcs or sparking on the wires.

    Could be an exhaust restriction too come to think of it...
     
  10. leolkfrm

    leolkfrm Full Member

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    how old is the gas in it?
     

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