1993 Cadillac sts 4.6 idle fluctuating
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Northstar Engines and System Technical Discussion Discussion, 1993 Cadillac sts 4.6 idle fluctuating in Cadillac Engine Technical Discussion; I start my car in the morning idle goes from 1000 to 2500 RPM S I'd tried puting it in ...
  1. #1
    savage3000 is offline Cadillac Owners Member
    Automobile(s): 1993 STS
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    1993 Cadillac sts 4.6 idle fluctuating

    I start my car in the morning idle goes from 1000 to 2500 RPM S I'd tried puting it in gear cannot drive it tell about 20 minutes and it goes back down to normal I replaced the ISC and it still does the same thing can anybody please help me I would like to thank you now for your help.

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  3. #2
    Ranger's Avatar
    Ranger is offline Cadillac Owners Member
    Automobile(s): White Diamond '03 DHS (with DTS floor shift)
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    Re: 1993 Cadillac sts 4.6 idle fluctuating

    Look for a vacuum leak. Maybe around the intake manifold cover.

  4. #3
    savage3000 is offline Cadillac Owners Member
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    Thread Starter

    Re: 1993 Cadillac sts 4.6 idle fluctuating

    Ranger thank you very much for answering my question but I've found what was making my rpm to go up and down it was the gray wire in the plug that plugs into that EGR I've been reading so many of the same symptoms and no one has ever gave this answer. Ranger I believe you are the smartest person on this whole site and most responsible person I wish the rest of the people would follow in your footsteps

  5. #4
    Ranger's Avatar
    Ranger is offline Cadillac Owners Member
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    Re: 1993 Cadillac sts 4.6 idle fluctuating

    Thanks, but you give me FAR more credit than I deserve. There are several people here who probably are more knowledgeable than I.

  6. #5
    Pete315 is offline Cadillac Owners Fanatic
    Automobile(s): 95 Eldorado
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    Re: 1993 Cadillac sts 4.6 idle fluctuating

    got similiar problem. where is the EGR on these northstars? when you said the gray wire in the plug was bad, was it a vacuum gray wire or an electrical gray wire?

  7. #6
    Ranger's Avatar
    Ranger is offline Cadillac Owners Member
    Automobile(s): White Diamond '03 DHS (with DTS floor shift)
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    Re: 1993 Cadillac sts 4.6 idle fluctuating

    The EGR is to the right of the TB when looking over the drivers side fender. Big black canister with a plug on top.

  8. #7
    Krashed989's Avatar
    Krashed989 is offline Cadillac Owners Connoisseur
    Automobile(s): 94 Eldorado, and a 99 ETC
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    Re: 1993 Cadillac sts 4.6 idle fluctuating

    This os on my 94. Your 95 looks the same but without all the plastic stuff over it.


  9. #8
    Pete315 is offline Cadillac Owners Fanatic
    Automobile(s): 95 Eldorado
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    Re: 1993 Cadillac sts 4.6 idle fluctuating

    thanks, Ill check it out.

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