erratic idle
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erratic idle
My Super Duty has been acting up lately. About two weeks ago, it started with a rough idle. In the last few days, it became an erratic idle, varying between about 800rpm and 1200rpm in a few seconds. This is constant. When i turn on the heat, air or defrost, the idle varies with the compressor cycle. The truck will lurch when im driving it.....i can take my foot off the gas and it will speed up or slow down by itself and i found that the cruise control doesn't work. I checked the PCV valve and i have vacuum at both ends. I cleaned the throttle body and checked for any vacuum leaks but couldn't find any. The "service engine soon" light came on, but then off. The EGR valve and DPFE sensor are only about 6 months old and they are Ford parts. The IAC valve was replaced about three years ago(40,000 miles) with a Ford part. Does anyone out there have any ideas? Thanx
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Is there a reoccuring problem with the IAC? I have replaced mine within the last 6 months and while my idle doesn't seem to be rough or erratic, once the engine warms up if get the "lurching" described here. Any thoughts??
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First, what year is your truck?
But yes, Big Orn is probably right (again!), the IAC is probably not opening/closing.
The telling point is the A/C clutch engaging drops the idle.
If it were me, and I had to replace the IAC, I purposely would NOT go to Ford for it.
I'd get a Standard brand, Napa, Holley, anything but original equip. However, they probably all sell the exact same part that Ford has, but at half the price (which is still the reason I would go aftermarket).
Since you mention DPFE sensor, I am assuming you have an EGR valve. It could be leaking.
Since the check-engine light went on at least once, get it read for codes. It may still have the original fault in it, and you can go from there. Report back if you get the code out of the computer and we'll puzzle over it some more.
In the meantime, if you want to spend around $30 on a new IAC, and you don't have an Autozone around that can read codes for free, go for it.
art k.
But yes, Big Orn is probably right (again!), the IAC is probably not opening/closing.
The telling point is the A/C clutch engaging drops the idle.
If it were me, and I had to replace the IAC, I purposely would NOT go to Ford for it.
I'd get a Standard brand, Napa, Holley, anything but original equip. However, they probably all sell the exact same part that Ford has, but at half the price (which is still the reason I would go aftermarket).
Since you mention DPFE sensor, I am assuming you have an EGR valve. It could be leaking.
Since the check-engine light went on at least once, get it read for codes. It may still have the original fault in it, and you can go from there. Report back if you get the code out of the computer and we'll puzzle over it some more.
In the meantime, if you want to spend around $30 on a new IAC, and you don't have an Autozone around that can read codes for free, go for it.
art k.
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Originally Posted by krewat
First, what year is your truck?
But yes, Big Orn is probably right (again!), the IAC is probably not opening/closing.
The telling point is the A/C clutch engaging drops the idle.
If it were me, and I had to replace the IAC, I purposely would NOT go to Ford for it.
I'd get a Standard brand, Napa, Holley, anything but original equip. However, they probably all sell the exact same part that Ford has, but at half the price (which is still the reason I would go aftermarket).
Since you mention DPFE sensor, I am assuming you have an EGR valve. It could be leaking.
Since the check-engine light went on at least once, get it read for codes. It may still have the original fault in it, and you can go from there. Report back if you get the code out of the computer and we'll puzzle over it some more.
In the meantime, if you want to spend around $30 on a new IAC, and you don't have an Autozone around that can read codes for free, go for it.
art k.
But yes, Big Orn is probably right (again!), the IAC is probably not opening/closing.
The telling point is the A/C clutch engaging drops the idle.
If it were me, and I had to replace the IAC, I purposely would NOT go to Ford for it.
I'd get a Standard brand, Napa, Holley, anything but original equip. However, they probably all sell the exact same part that Ford has, but at half the price (which is still the reason I would go aftermarket).
Since you mention DPFE sensor, I am assuming you have an EGR valve. It could be leaking.
Since the check-engine light went on at least once, get it read for codes. It may still have the original fault in it, and you can go from there. Report back if you get the code out of the computer and we'll puzzle over it some more.
In the meantime, if you want to spend around $30 on a new IAC, and you don't have an Autozone around that can read codes for free, go for it.
art k.
Billspight,We have seen a few IAC's go bad quickly ,but not alot of them within 6 months.
Chk the ports to it they get clogged with carbon.
If after warmed up does the idle rpms go up and down 800-1200 thats IAC
But if you have a rough ldle with no jump or swing to the above I'd be looking at COP's/ Boots or plugs.
Rich
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Originally Posted by FortyFords
Art which guy were you talking to?
The second one with the lurching, well, that's best put in a new thread ...
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I've owned 4 fords and the IAC has been a problem on all of them. Now I include taking of the IAC and cleaning it out with spray carb cleaner every time I rotate my tires, which is about every 6 - 9 thousand miles. It's part of my regular maintenance, I haven't had a problem since.
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Originally Posted by mdpopo59
I've owned 4 fords and the IAC has been a problem on all of them. Now I include taking of the IAC and cleaning it out with spray carb cleaner every time I rotate my tires, which is about every 6 - 9 thousand miles. It's part of my regular maintenance, I haven't had a problem since.
thanks!
Last edited by billspight; Mar 17, 2006 at 01:45 PM. Reason: spelling
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Funny, five years and 23K miles later (lots of stop-and-go, idling, so more like 100K miles on the engine)...
No problems with the IAC...
Lucky?
Don't know, but I ain't TOUCHING it !
No problems with the IAC...
Lucky?
Don't know, but I ain't TOUCHING it !
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From: Maryland
Originally Posted by krewat
Funny, five years and 23K miles later (lots of stop-and-go, idling, so more like 100K miles on the engine)...
No problems with the IAC...
Lucky?
Don't know, but I ain't TOUCHING it !
No problems with the IAC...
Lucky?
Don't know, but I ain't TOUCHING it !
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Originally Posted by mdpopo59
You played the lottery lately? Let me know if you do so I can play your number. lol
2169846546874654368743543384368468743687
I get half!
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