1967 Ford Mustang

1967 FORD MUSTANG
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DJG3582
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  • 3 POSTS
1967 Ford Mustang 6 cyl

I have a 67 mustang that when I start it, it idels extremely rough. Sounds like all cylanders are not firing. I try and reve the engine and there does not seem to be much power. I relpaced the fuel filter, the fuel pump and changed the plugs. Not sure what else i should do.

thanks
Feb 22, 2009 at 10:13 AM
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RASMATAZ
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  • 75,988 POSTS
A rough idle - A large vacuum leak can lean the air/fuel mixture out to such an extent that an engine will not idle at all. An EGR valve that is stuck open at idle can have the same effect as a vacuum leak. So too can a loose positive crankcase ventilation (PCV) hose, a leaky PCV valve or the wrong PCV valve (one that flows too much air for the application). If somebody replaced the PCV valve recently, they may have installed the wrong PCV valve. The rough idle in all of these cases is caused by "lean misfire." The fuel mixture is too lean to ignite reliably so it often misfires and fails to ignite at all. Lean misfire will show up as elevated hydrocarbon (HC) readings in the exhaust, which may be enough to cause a vehicle to fail an emissions test.
Feb 22, 2009 at 10:19 AM
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