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99 5.9 v8 Engine miss above 3500

Discussion in 'Engine & Performance' started by Bear_Gibson, Nov 2, 2019.

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  1. Bear_Gibson

    Bear_Gibson Junior Member

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    Location:
    Cape Girardeau, MO
    Ram Year:
    1999
    Engine:
    5.9 magnum
    So about a week ago I noticed when I stand on the loud pedal above 3500 it feels like it starts missing. No codes are present. It otherwise runs great.

    1999 Ram 1500
    5.9 V8
    4x4

    The top end was overhauled in 2016, new heads, new plenum gaskets, timing chain etc.
    Cap, button, wires, and plugs were new then.

    It has a CAI, a more free flowing exhaust system, and a tune.

    The tune has been on since July with no issues.

    Sitting here at the keyboard wondering what it could be. Thought I'd see what others thought.

    Thanks in advance
     
  2. Fast69Mopar

    Fast69Mopar Senior Member

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    Have you verified that you have proper fuel pressure?
     
  3. JimW124

    JimW124 Junior Member

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    5.9Ltd. Diesel:
    Just curious, did it set an engine light or have you attempted to see if it stored diagnostic codes. Fast 69 Mopar could very well be correct on your fuel pressure. Check there first.
     
  4. Bear_Gibson

    Bear_Gibson Junior Member

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    I have not checked it yet, do these have the test port in 99? Im not under the hood often. Just to check fluids.

    It feels like an ignition miss. It's not constant. Maybe on miss every few seconds.
     
  5. Yeret

    Yeret The Village Drunk

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    Ram Year:
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    Engine:
    5.9 Magnum
    '99 has a test port on the driver's side rail. I know because I have a '99 and I've tapped it more than once.

    How old is your catalytic converter, assuming you have one installed? It could be in the beginning stages of becoming clogged, and it's only downhill from there.
     
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  6. Bear_Gibson

    Bear_Gibson Junior Member

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    Ram Year:
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    I know it's not the cat. I did that a couple of years ago. it has a magnaflow y pipe and a spun converter. Friday after waiting for traffic to turn I leaned into it pretty good and got a heavy miss that cleared up after I let out some. Engine light flashed, I scanned it and a a pending cylinder 4 misfire code. So today I pulled the plugs, which I think I replaced in may of 16 when I did the heads. it had about .050 gap, instead of .040. I checked them all and found they were all above .040. So I re-gapped them. I plan to replace them as soon as I can get the boat out of the garage. What do you think? Is .050 more than the stock coil can handle. I have an OE style msd coil for the truck, I just never installed it. This miss feels like ignition to me, too harsh and sudden to be fuel.
     
  7. Yeret

    Yeret The Village Drunk

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    OEM plug gap is .040". Wouldn't recommend going wider with a factory coil. The MSD coil would probably fire .050" gap fine, but general consensus is aftermarket, high-output coils yield no benefits in our engines.
     
  8. Bear_Gibson

    Bear_Gibson Junior Member

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    I alway wondered about those coils.

    .050 was the worn gap. I think they are worn .010 over. I put them back to .040 but it did

    If new champions don't fix it then I plan to look at the distributor cap
     
  9. JohnnyMac

    JohnnyMac Hold my beer and watch this..... Military

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    My 2000 5.9 seemed to go through distributor caps like they were candy. Especially if I replaced with a cheap aftermarket....which I usually did.
     
  10. Bear_Gibson

    Bear_Gibson Junior Member

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    Engine:
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    I remember having trouble with my 318 Dakota's cap before, but I don't remember the symptoms. It's been almost 10 years since that happened.
     

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