Idle speed for 5.4
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Lead Driver
Joined: Nov 2008
Posts: 8,450
Likes: 70
From: South Jersey
Posted in the mod motor section with no responses so I'm posting here. 2004 super duty what's the idle suppose to be with a 5.4 motor?? Google didn't help with searching and all I could really find was in the Ex section but it was V10 are around 750rpm, I would assume my 5.4 should be around the same correct? Because mine is like 625-650rpm iPhone from IB AutoGroup
Postmaster
Joined: Sep 2010
Posts: 3,472
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From: Southern Cal
I'd expect to see about 750 also. Most importantly, is it idling well, not misfiring or running rough, or dying when putting it in gear? No vacuum leaks?
If not, it might be your add on's in your signature, or a dirty MAF. Check your IAC valve too.
If not, it might be your add on's in your signature, or a dirty MAF. Check your IAC valve too.
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Lead Driver
Joined: Nov 2008
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From: South Jersey
I've had a occasionally low idle issue when I first start the truck. It's been at least five to six years now, start truck it jumps to 1200 then comes down but it doesn't stop at 650 it drop to 500 rumbles and then kicks back up and is fine. I've replaced cleaned mass air IAC throttle position sensor changed plugs boots you name it. Don't fuel pressure tests and other tests, done vacuum tests and had it to two mechanics and all has checked out normal. I'm at the point I might have a program issue with the computer on the truck maybe. That's why I asked about idle because only the computer can adjust the idle
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Lead Driver
Joined: Nov 2008
Posts: 8,450
Likes: 70
From: South Jersey
Mines 630-650 ALL THE TIME, regardless of in P or D or R 2, and 1. Same wether it's winter or summer cold motor or fully warmed up... I just can't figure out why? I don't want to spend more money that I don't have for a dealer or regular mechanic to run test and tell me for the third time everything checked within specs and normal ranges
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Fleet Mechanic
Joined: Nov 2011
Posts: 1,825
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From: Land of Taxes
No current or stored codes right?
Are you reading the RPMs with a known good tach?
Whats cold in your neck of the woods?
Have you hooked it up to a diag machine to see what the O2 sensors, MAF, IAC and TPS are reading. Any of these malfunctioning could be telling the ECM/PCM that your all warmed up now and lean me out... reduce my idle etc....Could be a combo of two or more parts that are right on the edge of bad? Have to see the what the feed back loops are reading.
Another often overlooked item is vacuum leaks that arent on the engine. This has a negative effect on the computer (obviously) as it will mess with the fuel trim and injector timing etc. Check for leaks at the brake booster, HVAC system etc....Though to mess with, and over whelm the computer, the leak would need to be rather large and your fuel economy would be noticeably way down.
Do you have any other drivability problems?
The fact that you not getting high idle when its cold; Id start down that road to see whats up there.
Are you reading the RPMs with a known good tach?
Whats cold in your neck of the woods?
Have you hooked it up to a diag machine to see what the O2 sensors, MAF, IAC and TPS are reading. Any of these malfunctioning could be telling the ECM/PCM that your all warmed up now and lean me out... reduce my idle etc....Could be a combo of two or more parts that are right on the edge of bad? Have to see the what the feed back loops are reading.
Another often overlooked item is vacuum leaks that arent on the engine. This has a negative effect on the computer (obviously) as it will mess with the fuel trim and injector timing etc. Check for leaks at the brake booster, HVAC system etc....Though to mess with, and over whelm the computer, the leak would need to be rather large and your fuel economy would be noticeably way down.
Do you have any other drivability problems?
The fact that you not getting high idle when its cold; Id start down that road to see whats up there.
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Lead Driver
Joined: Nov 2008
Posts: 8,450
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From: South Jersey
-No codes other than that dumb P1000 -My SCT X3 to verify -Had it at my local ford dealer and a independent guy I trust -was told all checked out normal -winter here in Nj is 30's to 0* - truck does idle at 1200rpm maybe little higher when it warms up in the winter or when it chilly outside -truck drives normal, MPG are at 11mpg the past two/three months -ur other questions no I don't have an answer iPhone from IB AutoGroup
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Elder User
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No codes other than that dumb P1000
There are several possible causes for your symptoms. The most likely is a faulty IAC or the wiring/connectors for the IAC. Someone needs to look at live data with a good scanner to isolate the problem.
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Lead Driver
Joined: Nov 2008
Posts: 8,450
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From: South Jersey
Ever time I plug in my SCT it always pulls the P1000 code, I haven't had a tune in my truck for almost a year nor have I had the SCT hooked to the truck. But I'm positive I can go plug it in right now and it will pull a P1000
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