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rough idle/puffing blue

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Old Mar 25, 2008 | 02:18 PM
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1991 ford f-250's Avatar
1991 ford f-250
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Exclamation rough idle/puffing blue

its a 89 f250, 5.0l 302 FI. it has a super rough idle, and it puffs blue, when i give it some gas its good up until about half throttle, then it seems to bog down. any ideas?, are there any sensors that have a direct connection with how it idles, any and all information will be very very helpfull. Thanks
 
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Old Mar 25, 2008 | 03:01 PM
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ive pulled the codes, and something is there, i need some help to decifer them..
 
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Old Mar 26, 2008 | 11:45 AM
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blue beast
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What is the codes? A vacuum gauge can tell you alot about the motor and even point
to bad rings, bad valve, weak valve spring this is stuff the comp. can't tell you and a
compression test is only telling you half the story. http://www.mityvac.com/pages/products_hvpk.asp#07000
Go to model 7000 and then user manual and rent or buy a gauge and do the tests.
 
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Old Mar 29, 2008 | 12:54 AM
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Also check the fuel pressure from the schrader valve on the fuel rail. Should be 30-35 lbs. My fuel pressure regulator went bad recently and my pressure was up at 80lbs, up and down idle, and running way rich. Threw codes for O2 sensor and running rich.

There are some good posts on idle and running rich problems on the 87-96 forum.

If you're running blue smoke, that's oil; black is running rich. If you're sure it's blue smoke, I'm thinking head gasket? Are you getting oil in the coolant, or vice versa?
 
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Old Mar 29, 2008 | 02:27 AM
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I dont think the head gasket is my problem, this all started when it was swamped. The first half of my throttle runs good, after that its gutless. Its like my gears got cut in half
 
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Old Mar 29, 2008 | 04:40 AM
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check the cats... sound like they are clogged...
 
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Old Mar 29, 2008 | 02:56 PM
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the cats? i have never heard of these?
 
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Old Mar 29, 2008 | 03:24 PM
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Catalytic converters in the exhaust system. I've never experienced bad ones before, but many have. Supposedly a [trusted] exhaust shop could tell you if that's an issue. Or I suppose you could unhook and run around with straight pipes and see if it changes anything...although the lack of back pressure might affect something, I'm not sure.
 
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