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  • 1965 - 1973 Classic Mustangs -General/Talk-

Engine Is Racing

  • Thread starter Thread starter Hotroddoc
  • Start date Start date Aug 7, 2015
H

Hotroddoc

New Member
Aug 6, 2015
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0
1
Aug 7, 2015
#1
  • Aug 7, 2015
  • #1
i'm helping my friend who has a 66 Mustang with a 289 engine and has an aftermarket intake manifold with a Holley carb. Before he put it away a year and a half ago, he noted that the engine would race uncontrollably. Starting it up this year, same problem.

The linkage is working normally (nothing sticking). We noticed he had a vacuum leak on the manifold that we fixed.

Does anyone have any ideas what could be going on? I do not recall if it has an electric fuel pump.

Thanks,

Gary
 

afast93stang

Founding Member
Jan 6, 2002
1,407
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Aug 7, 2015
#2
  • Aug 7, 2015
  • #2
My 67 did that until i figured out that a spark plug boot had worked its way loose enough to affect the idle and i had tuned it unknowingly based on 7 cylinders firing which caused the engine to race. Once that plug was fixed i redid the tune and it was fine.
 
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