2018 Mustang 5.0 random cylinder misfire e85

Discussion in 'V8 5.0L Engine / Mods: Bolt-ons, Exhaust, Tuning' started by Chris5.0coyote, Feb 23, 2020.

  1. Chris5.0coyote

    Chris5.0coyote Active Member

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    My car has 33k miles cobra jet manifold stainless works Catless longtubes borla catback I was on 91 pump gas tune was fine for about 7kmiles but now I went e85 and datalogged for Lund tuning and tuner said the datalogs looks great I’ve drove the car to the track mabie did 7 passes was fine next day drove a hour did some roll racing and was fine turned back around to go home normal driving cruise control 80mph home and p300 p302 p304 came up I parked the car at home changed the plugs and 4 had the white porcelain cracked cleared the codes filled e85 again and drove it another 1k miles and did a couple runs was fine took it out the following Weeknd and drove it and the same codes came back up again !! Sent a email to my tuner he said go back to flex fuel tune and pump different gas it might not like the e85 I’m pumping so I’m Gona try that and I’m also Gona go back to 91gas on the flex fuel just throwing me off idk what to do any ideas ?
     
  2. MiDiablo

    MiDiablo #JustA4Banger

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    Have you checked the plugs again after the second incidence of the random misfires?

    Also, has the car been stalling randomly and intermittently?
     
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    Chris5.0coyote

    Chris5.0coyote Active Member

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    I haven’t pulled the plugs yet I’ll be doing that today or this week also the car does have like a small random rpm drop of like 100 mabie 200 every other time coming to a stop when I come to stop I push the clutch in and roll going into first and when I pull the clutch out to put it in neutral the car jumps back up to the RPMs that where dropped of that makes sense also when I first had pumped e85 and had to let the car learn the gas and change flag from 0 to 1 it did have like two times where it kinda wanted to stall but hasn’t happen since the car also pulls super crazy strong no lag or anything
     
  4. MiDiablo

    MiDiablo #JustA4Banger

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    So I'm not saying you're experiencing the exact same thing as my case, yet in my personal car we found the intake cams to be moving uncommanded. New cam phasers and solenoids going in this week to hopefully cure.
     
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    Chris5.0coyote

    Chris5.0coyote Active Member

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    Dam hopefully I don’t needa go that far into the motor I know how to do minor motor work but that’s Gona be a challenge for me I have time it’s The Weeknd car but still !

    are you boost or n/a where you having the problems only on e85?
     
  6. MiDiablo

    MiDiablo #JustA4Banger

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    Definitely a PITA, and I do this shit everyday, lol.

    Car is currently boosted, but symptoms began when car was NA E85 Lund tuned. Never went away. Got progressively worse over time, under boost. So tearing down the ole gal for replacements and OPG/CS/ARP bolt upgrades while we're in there.
     
  7. Cory S

    Cory S Well-Known Member

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    NGK 6510's @ .026-.027" gap?
     
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    Chris5.0coyote

    Chris5.0coyote Active Member

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    I’ve been using the stock pre gapped motor craft plugs
     
  9. Cory S

    Cory S Well-Known Member

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    Ummm... I would swap them out for 6510's @ .027" immediately and test again.
     
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    Chris5.0coyote

    Chris5.0coyote Active Member

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    You have a link where I can buy them ?
     
  11. Whitedevil95

    Whitedevil95 Well-Known Member

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    www.google.com
     
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    Chris5.0coyote

    Chris5.0coyote Active Member

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    lemme know if you find them on google.com
     
  13. Whitedevil95

    Whitedevil95 Well-Known Member

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