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  #16  
Old 11-29-2010, 06:46 PM
Fordzilla80 Fordzilla80 is offline
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Default Re: Idle fluctuates low

I have a 3.0, but the IAC works the same no mater what. I was having a problem with my truck where it would only run good under acceleration. At stops, the idle would drop down to 300 rpms, and the truck would attempt to die, unless it was held at 750 manually. I replaced the IAC with one from a parts truck, and that fixed it....for a month. Then that one started to act up, but it just dropped down to 500 rpms, and no lower. I got a brand new IAC from Auto Zone (didn't want to get one from Ford in case something else is throwing out my IAC's), and so far so good, she's idling great.

Cleaning the IAC didn't help me either time, and seems to only work when the truck just starts to develop the problem.
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  #17  
Old 11-30-2010, 06:55 PM
rangerscooby rangerscooby is offline
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Default Re: Idle fluctuates low

Clean IAC valve or replace, clean MAF sensor, Throttle body, replace pcv valve you would be surprised at the difference that makes, and replace any bad vacuum lines. The truck I got from my father would mostly idle low when putting in gear and had like a dead spot and then would idle back up and run rough, I replaced vacuum lines, new air filter, and pcv valve and made a huge difference, and later replaced the IAC valve that took a lot of the idle up and down out. I had two hoses that were bad, one on top of motor and one that I think is a fuel vacuum line on driver-side of vehicle, not sure if this helps any just thought it was worth mentioning
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  #18  
Old 12-01-2010, 08:46 AM
deason deason is offline
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Default Re: Idle fluctuates low,codes say it is lean

I have 2001 Ranger with a 3.0,i have my check engine light on,had it tested and it came back with 2 codes saying it was the maf.i bought the maf and replaced but was running the same.I am now replacing all the plugs and wires(found spots where it was arcing.if this dont work what should i look for next?Any help is appreciated
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  #19  
Old 12-01-2010, 09:08 AM
modelageek modelageek is offline
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Default Re: Idle fluctuates low

Deason. What are the actual code #,s? What areyour symptoms?

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Deason.... motorcraft or autolites plugs and wires are the recomended parts around here
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2004 Ext Cab, 4WD, 4.0, Auto, 154k. (4.0 engine is out of a 2009 Ranger w/96k) ( as of 7/1/2017)

2004 Ranger, Ext Cab, 2WD, 3.0, 5 speed , 4WABS, crank windows, no cruise, Edge 116k.(6/5,2014) (SOLD).
1999 Ford Ranger, Reg Cab, 2.5, 5 speed, 2WD, no AC, 150k (SOLD).
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  #20  
Old 12-01-2010, 09:12 AM
deason deason is offline
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Default Re: Idle fluctuates low

cant find the paper i must have left it at auto zone,anyway it said that if 2 codes came up it was the maf or fuel pump.we got the test tools and the fuel pump is holding at 60 to 65.so we have crossed that off the list.we got the maf last night replaced it and still running the same,we are now replacing the wires and plugs.the thing we are wondering is if it takes time to have the new maf on for it to run better.the truck runs fine in the am but in the pm will ildle down to die and have a hard time getting it started again.did we do a bad thing by returning the maf?
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  #21  
Old 12-01-2010, 09:19 AM
modelageek modelageek is offline
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Default Re: Idle fluctuates low

Deason we realy need the codes. Could be a vacuum leak.I am donna guess lean codes. The fuel pressure is fine
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2004 Ext Cab, 4WD, 4.0, Auto, 154k. (4.0 engine is out of a 2009 Ranger w/96k) ( as of 7/1/2017)

2004 Ranger, Ext Cab, 2WD, 3.0, 5 speed , 4WABS, crank windows, no cruise, Edge 116k.(6/5,2014) (SOLD).
1999 Ford Ranger, Reg Cab, 2.5, 5 speed, 2WD, no AC, 150k (SOLD).
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  #22  
Old 12-01-2010, 09:21 AM
deason deason is offline
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Default Re: Idle fluctuates low

yes it did say lean,its just trial by error till we get it right,lol,im the wife and he is working on it now.any help would be appreciated
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  #23  
Old 12-01-2010, 09:26 AM
modelageek modelageek is offline
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Default Re: Idle fluctuates low

Deason clean out the IACV and look around for a vacuum hose that is loose or cracked

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Deason it is most likely a vacuum leak. Look for loose or cracked vacuum line
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2004 Ext Cab, 4WD, 4.0, Auto, 154k. (4.0 engine is out of a 2009 Ranger w/96k) ( as of 7/1/2017)

2004 Ranger, Ext Cab, 2WD, 3.0, 5 speed , 4WABS, crank windows, no cruise, Edge 116k.(6/5,2014) (SOLD).
1999 Ford Ranger, Reg Cab, 2.5, 5 speed, 2WD, no AC, 150k (SOLD).
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  #24  
Old 12-01-2010, 10:04 AM
modelageek modelageek is offline
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Default Re: Idle fluctuates low

Deason also look along the pcv hose for cracks etc......

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also ask your wife to create a detailed profile of your truck.use mine as a templet if you like......it helps alot.........it is flex fuel?
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2004 Ext Cab, 4WD, 4.0, Auto, 154k. (4.0 engine is out of a 2009 Ranger w/96k) ( as of 7/1/2017)

2004 Ranger, Ext Cab, 2WD, 3.0, 5 speed , 4WABS, crank windows, no cruise, Edge 116k.(6/5,2014) (SOLD).
1999 Ford Ranger, Reg Cab, 2.5, 5 speed, 2WD, no AC, 150k (SOLD).
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  #25  
Old 12-01-2010, 10:50 AM
deason deason is offline
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Default Re: Idle fluctuates low

not flex fuel,and will have a detail about the truck asap,thanks
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  #26  
Old 12-11-2010, 02:39 PM
gshockxc gshockxc is offline
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Default Re: Idle fluctuates low

I cleaned my IACV today, and it improved slightly. The idle held steadier at about 600 rpm.

I noticed that my IACV had shiny marks on the actuator rod. So, I know it's still working, but I can tell by the difference between shiny and dirty that it's been this way for a LONG time. It looks like a simple spring/plunger system. With the spring, seats, rod, plunger, clips, etc, it looks like there's a lot of clap-trap in there to clean. Even with the q-tips, I don't see it ever getting really clean, no matter how much I spray it. I also noticed that the inner surface is rough, like a casting. So it's a perfect spot to catch debris. Regular cleanings are a must, as stated previously. I'm going to run it for a while and see if it improves any further.

Does the ECM need to adjust to the IACV over time? When I replaced the EGR tube, I noticed that the engine ran better right away, but it continued to improve slightly over time... better mileage, even with snow tires. I'm just wondering if the same will happen after cleaning the IACV.
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  #27  
Old 12-11-2010, 03:09 PM
Fordzilla80 Fordzilla80 is offline
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Default Re: Idle fluctuates low

No, it is impossible to fully clean the IAC. The majority of the time, cleaning the IAC doesn't completely fix the problem, it just masks it for a little bit. If the IAC was operating poorly, but after the cleaning it started to operate better, than I would imagine the computer would have to adjust a few things to compensate for the fix.
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  #28  
Old 12-12-2010, 11:22 AM
ekandresen ekandresen is offline
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Default Re: Idle fluctuates low

Quote:
Originally Posted by gshockxc View Post
I cleaned my IACV today, and it improved slightly. The idle held steadier at about 600 rpm.

I noticed that my IACV had shiny marks on the actuator rod. So, I know it's still working, but I can tell by the difference between shiny and dirty that it's been this way for a LONG time. It looks like a simple spring/plunger system. With the spring, seats, rod, plunger, clips, etc, it looks like there's a lot of clap-trap in there to clean. Even with the q-tips, I don't see it ever getting really clean, no matter how much I spray it. I also noticed that the inner surface is rough, like a casting. So it's a perfect spot to catch debris. Regular cleanings are a must, as stated previously. I'm going to run it for a while and see if it improves any further.

Does the ECM need to adjust to the IACV over time? When I replaced the EGR tube, I noticed that the engine ran better right away, but it continued to improve slightly over time... better mileage, even with snow tires. I'm just wondering if the same will happen after cleaning the IACV.
You need to disconnect the battery for 10 minutes and then allow the ecm to relearn the idle over several drive cycles. I have found cleaning is temporary, it should be replaced
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  #29  
Old 01-12-2011, 02:24 AM
gshockxc gshockxc is offline
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Default Re: Idle fluctuates low

Well, I've cleaned the MAF, replaced the IACV, and replaced the EGR valve, and each time, the engine idles better for about a day or two and then it starts to struggle at idle once it's been warmed up. So based on everyone's advice, it sounds like I've got some leaking vacuum lines.

Not having worked on vacuum lines, what are they ways to look for a leak? I saw another post that recommended spraying WD-40 near the throttle body and listening for changes in engine idle. Is that it? Is that the best way to check for a leak?

I'm not even sure I know where all the vacuum lines are. Obviously, there's a small one on the EGR I just replaced, and I think there's another one coming off the side of the valve cover, near the air intake hose. But beyond that, I'm just guessing.

Are there diagrams for this stuff? Or do I just go through my Haynes manual and look for every reference to an engine/fuel management sensor, see if it has a hose and check for a leak?

Thanks for the help.
p.s., if you're in the northeast, start shoveling!
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  #30  
Old 01-12-2011, 02:38 AM
modelageek modelageek is offline
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Default Re: Idle fluctuates low

There should be a diagram of the vacuum lines on the radiator support area
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2004 Ranger, Ext Cab, 2WD, 3.0, 5 speed , 4WABS, crank windows, no cruise, Edge 116k.(6/5,2014) (SOLD).
1999 Ford Ranger, Reg Cab, 2.5, 5 speed, 2WD, no AC, 150k (SOLD).
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