1992 Cadillac Deville EGR valve

Tiny
REARDRIVE
  • MEMBER
  • 1992 CADILLAC DEVILLE
  • 4.9L
  • V8
  • RWD
  • AUTOMATIC
When I first start the engine it run fine but as it warm up the motor start running different, in a few minutes it start back running fine. Can it be the EGR valve or the map sensor are going bad
Monday, May 12th, 2014 AT 8:27 AM

5 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,747 POSTS
When it starts running bad, can you describe what it does? Also, has the check engine light come on? Last, have you checked things like fuel pump pressure, the catalytic converter to see if it is plugging, check for vacuum leaks?
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Monday, May 12th, 2014 AT 9:06 AM
Tiny
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When car start running bad it sound like it is serging up and down, no check engine is on and no the fuel pump and catalytic converter havent been check out
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Monday, May 12th, 2014 AT 10:14 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Is the surging only at an idle?
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Monday, May 12th, 2014 AT 10:36 AM
Tiny
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Yes
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Monday, May 12th, 2014 AT 12:47 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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My first guess is either you have a vacuum leak or the idle air control valve (IAC) is going bad. The IAC is responsible for maintaining a smooth idle speed.
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Monday, May 12th, 2014 AT 5:54 PM

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