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Stumbling 4.3 TBI

Discussion in '1983-2005 S-Series models' started by mnstr_fx, Apr 2, 2002.

  1. mnstr_fx

    mnstr_fx Registered Member

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    My 91' 4.3 TBI S-10 pickup has this nasty habit of dieing on me after I let off the gas and come to a stop. I have checked the IAC, even cleaned the pintle end but this did not help it. I downloaded WinALDL and watched the engine parameters while I drove and checked that Yes, the IAC is moving and appears to be working. (Confused??) The final wierd part of this is that during my testing, I slipped the ECM into ALDL mode and the truck NEVER DIED! It ran VERY smooth.

    So, now that I am confused, could it be something else. Bad injectors?, ..... Has anyone else had this problem. The truck has ~150,000 on it and had a tune up a little while back, (plugs, wires, cap, rotor, TPS sensor). BTW it is a 5 speed truck.
     
  2. outsider223

    outsider223 1/2 ton status

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    I have a problem similiar to this with my 91 sonoma with the 4.3L and 150,000+ miles. After driving for a while and getting the engine good and warm, when i would stop at a light, it didn't die, but it idled really rough. It doesn't happen anymore, but i don't think i ever got it fixed.
     
  3. mnstr_fx

    mnstr_fx Registered Member

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    This truck only started to do it a few hundred miles ago. It is an extra truck which is not driven everyday, so I don't get too mad at it but I really need to get this fixed. If my dad borrows it, he gets mad. Anyone else ever had any of these symptoms. I don't want to start replacing everything and then see if it is fixed.
     
  4. BurbinOR

    BurbinOR 3/4 ton status

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    My wife's 4.3L Safari van did that a few times............it was the EGR valve stuck open (or is that closed). Seems the winter fuel additives, and compounded by the fact we were in CA at the time with their crappy gas, caused it to happen.
     
  5. HarryH3

    HarryH3 1 ton status Author

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    Sounds like a pretty classic symptom of a bad or dirty EGR valve. If it sticks slightly open, the engine has a very hard time idling.
     
  6. mnstr_fx

    mnstr_fx Registered Member

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    Thanks for the replies. I was not thinking EGR. After I went through the usual tune issues thoughts, I was only thinking ECM electronics. (DUH) I will check the EGR this weekend.
     

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