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Rough Idle Issue

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Old Oct 27, 2009 | 08:41 PM
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Durst451's Avatar
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Default Rough Idle Issue

Hello, I'm not very experienced with cars yet so any help is appreciated. The car is a 98 trans am LS1 5.7L. It has dynatech headers and cold air intake. Cat converter was removed along with rear o2 sensors, AIR, and EGR.

I realize, after looking at posts on this website, that with the cat removed the engine may idle a little rougher, but it seems like mine is excessive. If I come to a stop the rpms will fluctuate momentarily then drops off. This occurs in all gears, although not as often when in Park or Neutral. Every once and a while I will get black smoke during fast accelerations.

Additional info, if it helps. I noticed after looking under the car that when the previous owner installed the headers he also spliced the o2 sensor wires in order to make them long enough to reach the wire harnesses. Unfortunately he just left the left over slack hang there openly. There are several scorch marks on the wiring from touching the exhaust. There is also some wiring exposed to the elements where he spliced the wires together. Would this contribute to the problem I'm having? I have already made plans on replacing the sensors.

Does anyone have any suggestions? Plan on getting my codes read over the weekend. Will post results.

-Durst451
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Old Oct 27, 2009 | 11:53 PM
  #2  
Hemi2Slo's Avatar
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From: A small town, MS
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Yeah I would replace the O2's for sure. A messed up MAF would also cause idle problems.
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