Surging while driving and runs rough

Discussion in 'SN95 4.6L Mustang' started by sharkbait11, Nov 5, 2009.

  1. sharkbait11 New Member

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    Ok well it is running just not well.


    I have a guess of what it is but im not sure.

    Ok so im in 1st and about to merge off a ramp onto a highway. (Lots of traffic).
    I found my spot were I needed to merge and gave it a good id say 7/8 throttle... went up to like 4-5k and the front end droped down and it sounded like it was going to stall out.

    Also when im on the highway or driving it sounds raspy. I feel like i have no power or like it wants to have power its just not.

    Also when I pass on the highway and go half trottle to pass someone (half is all this car needs to fly by) the car surges. Not sure how i can explain it, but it surges power wise in mid range and it really bothers me.

    I do have the stock fuel injectors on at the moment
    What do you think it is.



    Powerdyne 6psi, 78mm throttle body, magnaflow exhaust, 255lph BBK fuel pump.
  2. wmburns Active Member

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    Check your cats

    Sounds raspy.... Check the cats.

    Hit them with a rubber hammer and see if you can hear the insides moving around.
  3. sharkbait11 New Member

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    Its not an exhaust sound. its the motor.
  4. oxfordgt New Member

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    Do you have a wideband?
  5. sharkbait11 New Member

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    No I do not, I also cant afford one =/
  6. wmburns Active Member

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    Checking the cats is FREE.

    Check the EGR system. If it is allowing too much EGR flow, this will cause power loss.

    Look for VAC leaks (free).

    Clean your MAF. Use MAF cleaner (low cost).

    Post the long term and short term fuel trim values at idle and load. Also confirm the car speed as reported by the PCM. Monitor the timing during a run and see if the PCM is suddenly pulling timing.
  7. trinity_gt Active Member

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    Sounds like a fuel delivery issue. What year is the car? You're running a 6-psi Powerdyne with a 255lph pump and stock, 19# fuel injectors? You say they're on "for the moment": Can you explain this? What do you normally run and why are the 19s back on now?
  8. the98stang New Member

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    no one has mentioned the damn spark plugs!

    that was my very first thought....

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