5.0L (1979-1995) MustangTechnical discussions on 5.0 Liter Mustangs within. This does not include the 5.0 from the 2011 Mustang GT. That information is in the 2005-1011 section.
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Question from a friend:
My '86 Mustang GT is missing at high RPM. It starts missing at about 3500-4000rpm & it keeps getting worse. It won't rev over 5000rpm anymore.
It all started at one instant, not a gradual thing. I had got on it a few times earlier that night with no problems, it pulled strong all the way to 6500rpm. The first time it did it was when I was leaving a stop sign I was at full throttle & it wouldn't burn out, it usually smokes the tires easily all through first. It was making a sound like it had a big load on it, like the way it sounds when you try to climb a hill @ full throttle in 5th gear. It also sounded like it was backfiring alot.
Edit: it will rev to 7000 when in neutral
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Forced Induction & Engine Management Systems
yeah, could be the timing... Or, something in the firing. Check everything that has to do with firing. Make sure you don't have a plug wire or two laying against a header. Also, check out the coil wire to see if it may be grounding on something. Maybe even as simple as a rotor button inside the distributor. Check all this and get back, Jason
Jason Hogan (870)-483-3338
93 notchback supercharged
85 monte carlo w/ blown 502
67 Chevy II 406 w/ nitrous
I had the same thing in my 86' GT. I had stock wires resting on the headers that were worn thin a little bit.. Then I was working in the garage with dim light and could see it arc a little bit.. bought new MSD wires and coil. made sure they weren't touching headers. Night and day difference.
69Mach1 - warmed up 395W (AFR 185s) and Gforce T5 with hydraulic clutch, 3.50:1 posi, rack&pinion/tilt, 235/50ZR17x8 front & 285/40ZR18x9 rear, American Racing Nova wheels, all MSD, Holley 750, custom paint, headlight relays, Shelby drop & 2" lower all around, Hotwheels Redline scale is 1 to 1. http://photobucket.com/albums/v618/danaranda/69stang
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