Rough Idle v-10
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New User
Joined: Feb 2004
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From: Pittsburg NH
Rough Idle v-10
I've got a 99 superduty v-10, and recently it started idling real bad and when warm starts hard, but when driving its perfect. I've already replaced the pcv hose last year and double checked it, checked for and visible vacuum leaks, cleaned injectors, cleaned MAF, replaced fuel filter, and replaced plugs with no luck. It sounds like its loping in park but when in gear is fairly close to stalling. any help?
Thanks
Keith
Thanks
Keith
Lead Driver
Joined: Sep 2003
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From: Albuquerque
IAC Removal and Install Instructions
Sounds like that could be your IAC (Idle Air Control) valve. You can clean it or replace it. Here is a link in my gallery with a step-by-step on a "How to".
https://www.ford-trucks.com/user_gal...&albumid=22274
Good luck...and please post back with any results.
biz
https://www.ford-trucks.com/user_gal...&albumid=22274
Good luck...and please post back with any results.
biz
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Joined: Feb 2004
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From: Pittsburg NH
sorry I guess I forgot to mention that also, I replaced the iac about 30,000 miles ago and just removed it again to clean it, it looked fine inside, and seemed to move up and down easily.
Keith
Keith
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From: Pittsburg NH
Scanned with snap on scanner, no codes but I found the maf sensor voltage 1.31 at idle and the scanner says .7 should be idle, any opinions here at $125.00 my cost I want to be fairly sure before replacing.
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Joined: May 2005
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From: San Antonio, TX
You already tried cleaning it so you might as well replace it.
If you are having any other driveability problems such as unusual transmission shifting and poor fuel mileage that should all clear up as well.
Make sure you get a high quality one and DO NOT touch that wire in the center of it.
The Granatelli or other high flow MAFs will not show you any gains on a stock motor.
Have you replaced the O2 sensors lately?
If you are having any other driveability problems such as unusual transmission shifting and poor fuel mileage that should all clear up as well.
Make sure you get a high quality one and DO NOT touch that wire in the center of it.
The Granatelli or other high flow MAFs will not show you any gains on a stock motor.
Have you replaced the O2 sensors lately?
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From: Pittsburg NH
Originally Posted by JKBrad
You already tried cleaning it so you might as well replace it.
If you are having any other driveability problems such as unusual transmission shifting and poor fuel mileage that should all clear up as well.
Make sure you get a high quality one and DO NOT touch that wire in the center of it.
The Granatelli or other high flow MAFs will not show you any gains on a stock motor.
Have you replaced the O2 sensors lately?
If you are having any other driveability problems such as unusual transmission shifting and poor fuel mileage that should all clear up as well.
Make sure you get a high quality one and DO NOT touch that wire in the center of it.
The Granatelli or other high flow MAFs will not show you any gains on a stock motor.
Have you replaced the O2 sensors lately?
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Joined: Jul 2002
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From: Long Island USA
If it runs good under a load, and only does it at idle, I seriously doubt the MAF is malfunctioning.
On my '01 (granted, it's two years different), I can completely unplug the MAF and it doesn't effect the idle nor slight acceleration when moving the truck around the driveway.
Big question: Does it happen when cold AND warm?
On my '01 (granted, it's two years different), I can completely unplug the MAF and it doesn't effect the idle nor slight acceleration when moving the truck around the driveway.
Big question: Does it happen when cold AND warm?
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From: Long Island USA
Originally Posted by FortyFords
Dirty Maf or the IAC or fuel pressure .
Bad cop would cause miss all the time not just at idle.
Get it scanned with a good scanner for misfire codes
Rich
Bad cop would cause miss all the time not just at idle.
Get it scanned with a good scanner for misfire codes
Rich
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From: Pittsburg NH
Originally Posted by krewat
If it runs good under a load, and only does it at idle, I seriously doubt the MAF is malfunctioning.
On my '01 (granted, it's two years different), I can completely unplug the MAF and it doesn't effect the idle nor slight acceleration when moving the truck around the driveway.
Big question: Does it happen when cold AND warm?
On my '01 (granted, it's two years different), I can completely unplug the MAF and it doesn't effect the idle nor slight acceleration when moving the truck around the driveway.
Big question: Does it happen when cold AND warm?
I have also tried unplugging the maf and running it and no difference.
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From: Pittsburg NH
Well today I replaced the MAF sensor guess that was a waste of $125.00. Any other ideas , could the 02 sensors go bad without setting a code, the left side is constantly a little lower than the right for readings when scanned, but still fluctuatesup and down.
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Joined: Jan 2002
Posts: 5,859
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From: USA
Did you chk the fuel pressure at the rail ? at Idle and under load?
The o2 sensor is what sets the fuel trim after your in open loop.If you think this is the cause,watch the fuel trim for that side and then switch the o2's and see if the fuel trim fluctuates no on the otherside.
But I'm one for verifying bad parts before just changing them .
I never said change the maf ,just clean it and reset the pcm for relearn process.
Rich
The o2 sensor is what sets the fuel trim after your in open loop.If you think this is the cause,watch the fuel trim for that side and then switch the o2's and see if the fuel trim fluctuates no on the otherside.
But I'm one for verifying bad parts before just changing them .
I never said change the maf ,just clean it and reset the pcm for relearn process.
Rich
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From: Pittsburg NH
Not blaming you, I replaced the Maf because the voltage at idle was not what was specified from the meter, I guess i was just hopeful that would cure the problem, but i'm not a parts replacier either there was a reason for it. I'll try to check fuel press. next and see what I find.
Thanks
Keith
Thanks
Keith
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From: Pittsburg NH
I checked the fuel press this morning
At idle approx. 35 psi.
Under load climbing hill 40 psi.
I beleive these are normal but not sure.
Also since this problem started it hasn't been cold outside but this morning it was 45 degrees, It idled higher (normal) when cold and sounded much better but within a minute (I assume when it hit open loop mode) it was running rough again.
Keith
At idle approx. 35 psi.
Under load climbing hill 40 psi.
I beleive these are normal but not sure.
Also since this problem started it hasn't been cold outside but this morning it was 45 degrees, It idled higher (normal) when cold and sounded much better but within a minute (I assume when it hit open loop mode) it was running rough again.
Keith