Surging at idle
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Freshman User
Joined: Mar 2005
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Surging at idle
I have a 99 350 dually. A week ago I got a check engine light and it was running a little weak. When I put my decoder on, it read a lean rt bank. I cleared the code and it did not come back. Now it surges at idle and is more distinctive when it is drive. It feels like I have a big cam it. (no codes) We checked the fuel filter and it was clean. Fuel pressure is good. We unplugged the mass air senser and it smoothed out. So I replaced the senser. Started it up and it ran fine for a while then started to surge again but not as bad. Any Ideas what to check now? Thanks
Logistics Pro
Joined: Jan 2002
Posts: 3,733
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Idle Air Control
Is up on pass side top---- right behind the throttle body and Controls the Air during Idle
Gets gummed up and stuck often...can be cleaned and reinstalled, use B-12 chem tool or similar, or just replaced..not very expensive part
Is up on pass side top---- right behind the throttle body and Controls the Air during Idle
Gets gummed up and stuck often...can be cleaned and reinstalled, use B-12 chem tool or similar, or just replaced..not very expensive part
Lead Driver
Joined: Sep 2003
Posts: 5,844
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From: Albuquerque
Originally Posted by Sundance Kid
What is the Iac control valve
https://www.ford-trucks.com/user_gal...&albumid=22274
biz
Post Fiend
Joined: Jan 2002
Posts: 5,859
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From: USA
Originally Posted by krewat
Having already checked the MAF, a lean code would probably be a vacuum leak - check the PCV plumbing (especially the elbow at the throttle body).
Rich
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Posting Guru
Joined: Nov 2004
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From: North Dakota
Kewart is on it, check the 90 degree PVC Elbow and associated plumbing. A guy I work with just got the exact same systems and code on his 5.4L powered expedition, it was a cracked elbow! It cost him a $100 to have someone find it and fix it. If he'd would have said something before he took it in I could saved him $98, lol.
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Post Fiend
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From: NE Texas
Originally Posted by SLE
Sorry forty, I only read the last couple of posts, Credit should be give where credit is due, lol!
Kudos to Farty!!!
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From: Long Island USA
Originally Posted by FortyFords
Must be a ECHO in here!!!!!!!!
Rich
Rich
Rich is DA MAN!
I just keep repeating what he, Fred, and lots of others have said here...
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Freshman User
Joined: Mar 2005
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This site rocks!!!! After reading everyones advice and a little looking under the hood. I found the culprit to my woes. It appears that you guys are more than a pretty face(ha ha ha). It was the rubber 90 degree elbow going to the pvc. It looked like it's gotten weak from oil deposits and collapsed from the vacuum tearing it at the bottom of the metal nipple. (did I say nipple!!!). If you would just look at it there was nothing physically wrong. I had to pull it off from under all the other crap to get a good look. The trucks running great again thanks to all of you! Just to recap for other folks. The motor was surging at idle and more distictive when it drive with the brake on. We found the MAF senser bad and the split on the rubber elbow. Once again thanks to all.