96 DeVille Needs Help. 0300 Missfire Code.
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Cadillac DeVille 1985 to 2005 including:
1985-1992 Fleetwood, 1993 Sixty Special, All FWD Forum Discussion, 96 DeVille Needs Help. 0300 Missfire Code. in Past Cadillac Vehicle Discussion; I have a 1996 Cadillac DeVille that needs to be registered but It wont pass smog and is running poorly. ...
  1. #1
    ralphieboy57 is offline Cadillac Owners Member
    Automobile(s): 1996 DeVille
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    Dec 2011
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    Fountain Valley, Ca
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    96 DeVille Needs Help. 0300 Missfire Code.

    I have a 1996 Cadillac DeVille that needs to be registered but It wont pass smog and is running poorly. At first it started getting hard to start when hot. Then it through the SES light. Plugged in my Obd II and it gave me the P0300 code (Random Missfire). Put new Plugs, Plug Wires, Air Filter, Fuel Filter, and cleaned the throttle body. Still throwing the 0300 code. Now it just started stalling at stops and motor hesitates when on freeway on even throttle, and when accelerating and when using cruse control. What is wrong? Is it the fuel pump!

    Any suggestions would be welcome.......Thanks.

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  3. #2
    rodnok01's Avatar
    rodnok01 is offline Cadillac Owners Connoisseur
    Automobile(s): 98 DeVille, 97 DeVille d'Elegance
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    Re: 96 DeVille Needs Help. 0300 Missfire Code.

    Have you checked the FP? A plug in OBDII scanner should give you the missing cylinder.

  4. #3
    Ranger's Avatar
    Ranger is offline Cadillac Owners Member
    Automobile(s): White Diamond '03 DHS (with DTS floor shift)
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    Re: 96 DeVille Needs Help. 0300 Missfire Code.

    Quote Originally Posted by ralphieboy57 View Post
    At first it started getting hard to start when hot.
    Yup, I'd put money on a leaky FPR.

  5. #4
    crabgrass's Avatar
    crabgrass is offline Cadillac Owners Member
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    I'm with ranger on the FPR. I had trouble with hot starts and kills at stop lights and that did the trick. Acdelco 2173083 if you have a base deville. $48 on rockauto

  6. #5
    ralphieboy57 is offline Cadillac Owners Member
    Automobile(s): 1996 DeVille
    Join Date
    Dec 2011
    Location
    Fountain Valley, Ca
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    Re: 96 DeVille Needs Help. 0300 Missfire Code.

    Thanks. I will try that before I replace the fuel pump. 50 dollars is a little less $$$ than a fuel pump.

  7. #6
    ralphieboy57 is offline Cadillac Owners Member
    Automobile(s): 1996 DeVille
    Join Date
    Dec 2011
    Location
    Fountain Valley, Ca
    Posts
    17

    Re: 96 DeVille Needs Help. 0300 Missfire Code.

    Quote Originally Posted by ralphieboy57 View Post
    Thanks. I will try that before I replace the fuel pump. 50 dollars is a little less $$$ than a fuel pump.
    Put in the FPR yesterday. Car runs great. SES light has stayed off. Idle is steady........Im stoked. Thank you Cadillac forums. This forum rocks!!!!!!!

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