Misfiring bad problem

Discussion in '94-95 5.0 - Specific' started by Yosoydominic, May 1, 2016.

  1. Yosoydominic

    Yosoydominic New Member

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    So my car will run perfect with the first start of the day. As I'm driving to work for example if I hit a bump my car starts to misfire. As I'm driving it'll keep bouncing rpms and I will hear back pressure from exhaust.
    If it's a case where I drive and the car doesn't misfire and I walk into the gas station and come out 5 minutes later I start the car and it starts jumping rpms from 1k - 2.5k
    I have no idea what problems could be and even my friends are stumped and we've replaced some things but can't seem to figure out what to check anymore.
    Anyone know what this may sound like or could be?
    I have a 1994 GT.
    Any suggestions appreciated and I can answer any further questions asked :(
     
  2. Frank.JD.Perez

    Frank.JD.Perez Well-Known Member

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    Do you have any coolant leaking? Does your oil look milky? Have you replaced any gaskets lately!
     
  3. the5.ohh

    the5.ohh Legend

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    If you hit a bump it misfires? Not being a smartass, but make sure everything is connected and bolted on where it ought to be. Car stock or modified?
     
  4. 95GT86SS

    95GT86SS New Member

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    This

    95 GT BBK CAI TB MSD 6AL O/R H SLP LM1
    Coming soon GT40 Heads Intake and e303 cam with Long tubes
     
  5. Yosoydominic

    Yosoydominic New Member

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    Oil is great just changed it last month. No coolant leaking anywhere I already fixed that when I threw in my new cooling system.

    Everything is connected I've already ran all my lines and nothing is brittle or broken or cracked so yeah. Only thing that's been touched is my timing and I advanced it 4 degrees other than that a new coil pack and thats it
     
  6. the5.ohh

    the5.ohh Legend

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    You advanced the timing, are you running a higher octane fuel? If you're still using 87, that's gonna most likely be your issue. You can't advance your timing and use the same grade fuel. Try 93 octane.
     
  7. Yosoydominic

    Yosoydominic New Member

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    I do use 93 octane. I'm still stumped and getting to switch my iac sensor and see what happens :(