1995 GMC Sonoma

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  #1  
Old 08-18-11, 03:00 PM
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Need help 1995 GMC Sonoma

When I first start then take off all is ok but after the first time I stop my truck accelerates very sluggish and then the transmission wont shift!! What is my problem??
 

Last edited by Packers48094; 08-18-11 at 04:57 PM. Reason: Need help
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  #2  
Old 08-19-11, 03:49 AM
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Your transmission is likely going into the "limp" mode; it's designed to do that if there is a problem so you can "limp" home or to a garage. It's usually one gear only and I think it'll be 2nd gear. At the very least you need to have it checked for codes to see if a tranny error code pops up; next stop after that would be a good independent tranny shop.
 
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Old 08-19-11, 04:11 AM
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Could it be a result of bad gas by chance, and what would happen if I keep driving it? oh and where can i get the codes cheched advanced Auto?? Thank you
 
  #4  
Old 08-19-11, 09:18 AM
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No, gas would have no effect. Yes, AutoZone and many of the other national parts houses will read codes for free (hoping you'll buy their parts). With transmission issues you're much less likely to be able to DIY the fix than with an engine issue, but at least you may get a clue as to what's up. If you keep driving it your major issue would be not being able to drive it over about, I'm guessing, about 25 mph or so without risking over-revving the engine. That limp mode is a lot like a "donut" spare tire; yes you can drive around on it, but it was really designed just to get you off the road.
 
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Old 08-19-11, 03:13 PM
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Is there a possibility that its the spend indicator for the transmission??
 
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Old 08-19-11, 07:33 PM
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"Spend indicator"???
 
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Old 08-19-11, 07:42 PM
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I beleive it tells the transmisson when to shift.
 
  #8  
Old 08-20-11, 04:08 AM
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That's a bit complicated. Actually the PCM tells the transmission to shift in modern electronically-controlled trannies after taking into account throttle position (via the TPS), engine speeed (via input speed sensor), transmsion selector position (via the range sensor) and other factors. This is not something you are likely to be able to fix by guesswork; you'll at least need codes or a diagnosis to see what the underlying problem is.
 
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Old 08-20-11, 07:08 AM
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Some also use the speed sensor off the wheels in addition to the others. Just had a similar issue on my son's 2002 Grand Am, and that is where the problem ended up being. A connection wire was worn through in this case but it was an input failure from the wheel sensor, the same one used for traction control I believe.
 
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Old 08-21-11, 04:00 AM
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Thanks eq; I seems to have missed vehicle speed in listing the inputs. Any or all of those should set a code; will have to see what the OP comes back with.
 
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