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94 S-10

HDChuck01

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HDChuck01 Enthusiast

HDChuck01

Posted
Posted

Hi all,

 

I have a 94 S-10 pickup 4.3L w auto tranny and I have an SES light on. The truck idles bad when in gear and at a stop and when starting to accelerate. On the highway it runs ok, She'll run good with my foot in it but can't drive like that all the time. I have not been able to find the OBD I port to connect a scanner. Went to a couple of auto parts stores and they could not find it either. If it's throwing a code (which it is) it has to have an access port doesn't it? Would anyone know off hand why she'd be running like that without checking the codes? I appreciate any help with this problem. This site is great for knowledge! :confused:

  • 3 months later...
neex Enthusiast

neex

Posted
Posted

I would start by verifying both vac and fuel pressure. If both check out ok, I would check all your sensors but start with both MAP, EGR and O2 sensors. It sounds like you are experiencing a misfire of sorts - have you checked the usual suspects?? (cap, rotor, wires).

 

You may want to pop the hood in darkness while the engine is running... Check for blue arcs/sparking. If you see arcing, you know that you have a short in your ignition system that's causing the misfire. I would bet either a bad EGR, fuel spider leaking or poppets not opening properly, or a dead short in an ignition wire or coil. You may want to test to make sure that your MAP sensor doesn't calculate fuel trim based on your truck being over 20,000ft!

 

Please let us know what tools you have at your disposal and we'll try to help you diagnose this.

 

Thanks.

Andrew.

 

 

 

 

 

 

 

 

<br />Hi all,<br /><br />I have a 94 S-10 pickup 4.3L w auto tranny and I have an SES light on. The truck idles bad when in gear and at a stop and when starting to accelerate. On the highway it runs ok, She'll run good with my foot in it but can't drive like that all the time. I have not been able to find the OBD I port to connect a scanner. Went to a couple of auto parts stores and they could not find it either. If it's throwing a code (which it is) it has to have an access port doesn't it? Would anyone know off hand why she'd be running like that without checking the codes? I appreciate any help with this problem. This site is great for knowledge! <img src="style_emoticons/default/thumb.gif" style="vertical-align:middle" emoid=":fume:" border="0" alt="thumb.gif" /><br />
<br /><br /><br />
  • 1 month later...
freakinbox Enthusiast

freakinbox

Posted
Posted

I was just about to say map sensor, my uncle had the same problems with my truck. Would have trouble to a certain speed then TAKE OFF.

I love how I got this truck with most of the expensive problems already fixed ;)

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