Rough Idle

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Jan 12, 2005 | 11:24 AM

Fordtruc526

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Joined: Dec 2003

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From: West Grove, Pennsylvania

Rough Idle

hey, i have an 89 f-150 with a 300 inline...when i first start it up and let it idle for a little bit..it starts to idle rough it jumps from like 1100 to 400 and i really annoys me cause i cant figure out the problem...ive heard rumors that it could be a bad O2 sensor but im not sure

any ideas?

Jan 12, 2005 | 12:11 PM

Silver Streak

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Joined: May 2002

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From: Broken Arrow, OK

Have you changed you fuel filter recently? Sounds kinda like the fuel pump is having trouble building enough pressure to start and run during its 2 second prime.

Jan 12, 2005 | 01:05 PM

srercrcr

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you might do a search. Someone else had the exact same problem.

Jan 12, 2005 | 05:30 PM

firststep25

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changed O2 sensor and fuel filter and no change in rough idle and missing during low rpm running.

Jan 12, 2005 | 08:01 PM

wickymustang

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Any codes thrown or stored? It could be the IAC needs to be cleaned or replaced as well.

Jan 18, 2005 | 11:17 AM

FBerger

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From: Murdock, KS

How about your brake booster? Mine idles rough too, and I know I need to replace it. If you pull off the vacuum line to it and plug it, see if it smooths out.