Hesitant at high rpm

Discussion in 'General Tech' started by 98BlackGT, Jan 28, 2014.

  1. 98BlackGT

    98BlackGT Well-Known Member

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    Ok so I posted on this before but my car is hesitsting at high rpm like 4500 when I'm gettin on it. It cuts for for a few seconds and goes back. I've done the following

    New plugs
    Checked fuel pressure
    New maf

    And a few other things I'm forgetting... Anyone have this problem/think they know what it can be? I'm hearing numerous things like fuel pump and fuel filter but I just changed the fuel filter 10k miles ago


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  2. Musturd

    Musturd Legend

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    Yea but not the fuel pump , it could be losing fuel uptop at high rpm where I'm sure you didn't check fuel pressure under load, you just used a gauge and checked it under the hood ? It could even be ignition related .
     
  3. Wild Horses

    Wild Horses Active Member

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    Had the same exact problem but mine was the plugs. Have you gotten wires or made sure they have made positive connection to the plugs? Sometimes it's the simplest things. It does sounds ignition related. A set of wires if they're due, and if that won't clear it up I'd try fuel filter, then coil packs before fuel pump. First thing I always do is triple quadruple check all connections.
    I messed with my old 5.0 for 2 days that wouldn't even start. Rearranged plug wires reset top dead center at one point thought my timing chain was broken. But nah the MSD negative lead was unplugged. Learned my lesson.
     
  4. 98BlackGT

    98BlackGT Well-Known Member

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    I just did a full tune up 10k miles ago and checked over everything recently. So I'm starting to think it's something else
     
  5. 98BlackGT

    98BlackGT Well-Known Member

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    Yeah I only checked it at regular idle
     
  6. CWO

    CWO Active Member

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    coil packs
     
  7. Wild Horses

    Wild Horses Active Member

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    You do have the dual coil pack set up right? I'd buy one if on a budget from a local parts store. Try it one side at a time. See how it acts. They usually don't fail at the same time. Find the side that's breaking down at high rpm. Return pack to parts store if no change. If you get even a little better then buy another pack and drive.

    Its ts easier to go through the ignition components first to be sure then to start dropping gas tanks for nothing.
     
  8. 98BlackGT

    98BlackGT Well-Known Member

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    Yeah dual coil packs, I have msd in there now. I have msd wires too and had ngk plugs, switched out plugs for autolites
     
  9. Wild Horses

    Wild Horses Active Member

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    What did you gap those autolites at? I pulled some autolites out of my 98 because it was missing at high rpm, and they were almost melted. I got NGKs gapped em at .48 and the car ran like a top after.
     
  10. 98BlackGT

    98BlackGT Well-Known Member

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    I had a shop do it
     
  11. Wild Horses

    Wild Horses Active Member

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    Hmm. Do you have the tools to pull the number one plug out? Easiest to get to on driver side. And was it missing before the shop visit?
     
  12. 98BlackGT

    98BlackGT Well-Known Member

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    Yes missing before shop visit. That's why it went in. I was working and had no time to work on it
     
  13. Wild Horses

    Wild Horses Active Member

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    It'd be ideal to get a look at at least one plug to see how it's gapped and burning.
     
  14. 98BlackGT

    98BlackGT Well-Known Member

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    Yeah once it gets nicer out here in NJ I'm gonna start going over it. There was not a big chance wen the plugs were changed though that's why I'm thinking it's definitely something else
     
  15. Wild Horses

    Wild Horses Active Member

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    Yea im in MD and it's Ben sub freezing for like 3 weeks. Just got 2" of snow last night.
     
  16. 98BlackGT

    98BlackGT Well-Known Member

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    We got one inch but I have the car in a garage finally for the winter