Poor Idle, 1998 Olds Cutlass 120,000 miles 3.1 liter

1998 OLDSMOBILE
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KKJJAA69
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Had 1998 olds cutlass on diagnostics machine. Read code po 300(random missfire). Can feel car shaking from poor idle when at stop sign. Could this be a bad egr valve? I have changed plugs, wires and coil packs.
Any help I would appreciate.

Also, How do you check for leaks in vacuum system?
Jun 11, 2007 at 8:30 PM
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BRUCE HUNT
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That is the place I would start is with the EGR. Take it off, clean it and retry. Note the condition of the valve for possible replacement. Don't forget the PCV off of the valve cover.

Testing vac lines is dependent upon the resources you have available. But a good ear and an attentive set of eyeballs will do wonders for picking up leaks.
Jun 14, 2007 at 7:34 AM
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