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Mechanics? Help Needed - 2006 Ford F-150 4.6L Idles Rough/Stumbles Login/Join 
Gimp with
The Limp
Picture of RBeach
posted Hide Post
quote:
Originally posted by Shifferbrains:
RBeach,

Make sure that the snorkel from the air cleaner to the intake is properly seated and tight, and there are no splits that can allow unmetered air into the engine.


I have confirmed this as that was one of the first things I was looking for.


RBeach
_________________________________
What if there were no hypothetical questions? - George Carlin
 
Posts: 2104 | Location: Fort Mill, SC | Registered: June 12, 2005Reply With QuoteReport This Post
Member
Picture of 1Lowtrk
posted Hide Post
Check the PCV and the hose going to it
 
Posts: 248 | Location: Burbank ill | Registered: May 13, 2010Reply With QuoteReport This Post
Just because you can,
doesn't mean you should
posted Hide Post
Back to the basics.
You mentioned the truck sitting around for a few months with the tank almost empty.
Have you run some dry gas through it in case some moisture got in there?
Kind of like chicken soup. Can’t hurt to try.


___________________________
Avoid buying ChiCom/CCP products whenever possible.
 
Posts: 9999 | Location: NE GA | Registered: August 22, 2002Reply With QuoteReport This Post
Just Hanging Around
posted Hide Post
Ford trucks of the 2004 - 2008 vintage had a fuel pump driver module (FPDM) mounted on the cross member above the spare tire. Water, crud, and mud get slung up there, and the bottom of the module gets eaten away exposing the electronics. Causes all kinds of problems. It would be worth checking.
 
Posts: 3292 | Location: NE Kansas | Registered: February 24, 2007Reply With QuoteReport This Post
Member
posted Hide Post
Look at the VCT variable camshaft timing solenoids on your truck 4.6L & 5.4L. This could be part of the problem. My 07' F150 started slowly having idling issues when slowing down or creeping along in bumper to bumper traffic. Got to the point that would start shaking like the engine would come out of the truck, but a tap on the gas would get it back to normal. Seems these valves get stuck or the screens get damaged and fail. On my 5.4L Ford changed the way these were accessed sometime during my model year. Went from a 15 minute DIY easy access through the valve cover, to a tear the engine apart and pay $800 bucks endeavor. A pair of them (OEM) should only be about $70 for a pair online (Rock Auto, 1A Auto, Parts Geek, etc). Ford dealer or online will charge about $70-80 per piece.



It's all about clean living. Just do the right thing, and karma will help with the rest.
 
Posts: 1156 | Location: The Republic of Texas | Registered: April 11, 2008Reply With QuoteReport This Post
Gimp with
The Limp
Picture of RBeach
posted Hide Post
quote:
Originally posted by 1Lowtrk:
Check the PCV and the hose going to it


New Motorcraft PCV valve and hoses checked. All were good.


RBeach
_________________________________
What if there were no hypothetical questions? - George Carlin
 
Posts: 2104 | Location: Fort Mill, SC | Registered: June 12, 2005Reply With QuoteReport This Post
Gimp with
The Limp
Picture of RBeach
posted Hide Post
quote:
Originally posted by 220-9er:
Back to the basics.
You mentioned the truck sitting around for a few months with the tank almost empty.
Have you run some dry gas through it in case some moisture got in there?
Kind of like chicken soup. Can’t hurt to try.


Yes. The tank was emptied and new gas put in.


RBeach
_________________________________
What if there were no hypothetical questions? - George Carlin
 
Posts: 2104 | Location: Fort Mill, SC | Registered: June 12, 2005Reply With QuoteReport This Post
Gimp with
The Limp
Picture of RBeach
posted Hide Post
quote:
Originally posted by Muddflap:
Ford trucks of the 2004 - 2008 vintage had a fuel pump driver module (FPDM) mounted on the cross member above the spare tire. Water, crud, and mud get slung up there, and the bottom of the module gets eaten away exposing the electronics. Causes all kinds of problems. It would be worth checking.


This was replaced as well.


RBeach
_________________________________
What if there were no hypothetical questions? - George Carlin
 
Posts: 2104 | Location: Fort Mill, SC | Registered: June 12, 2005Reply With QuoteReport This Post
Gimp with
The Limp
Picture of RBeach
posted Hide Post
quote:
Originally posted by sig226fan:
Look at the VCT variable camshaft timing solenoids on your truck 4.6L & 5.4L. This could be part of the problem. My 07' F150 started slowly having idling issues when slowing down or creeping along in bumper to bumper traffic. Got to the point that would start shaking like the engine would come out of the truck, but a tap on the gas would get it back to normal. Seems these valves get stuck or the screens get damaged and fail. On my 5.4L Ford changed the way these were accessed sometime during my model year. Went from a 15 minute DIY easy access through the valve cover, to a tear the engine apart and pay $800 bucks endeavor. A pair of them (OEM) should only be about $70 for a pair online (Rock Auto, 1A Auto, Parts Geek, etc). Ford dealer or online will charge about $70-80 per piece.


I had a friend I was trying to troubleshoot over the phone with and he mentioned the same thing. I cannot find the VCT solenoids on my engine. I have the 2V and not the 3V engine.


RBeach
_________________________________
What if there were no hypothetical questions? - George Carlin
 
Posts: 2104 | Location: Fort Mill, SC | Registered: June 12, 2005Reply With QuoteReport This Post
Member
Picture of PowerSurge
posted Hide Post
quote:
Originally posted by sig226fan:
Look at the VCT variable camshaft timing solenoids on your truck 4.6L & 5.4L. This could be part of the problem. My 07' F150 started slowly having idling issues when slowing down or creeping along in bumper to bumper traffic. Got to the point that would start shaking like the engine would come out of the truck, but a tap on the gas would get it back to normal. Seems these valves get stuck or the screens get damaged and fail. On my 5.4L Ford changed the way these were accessed sometime during my model year. Went from a 15 minute DIY easy access through the valve cover, to a tear the engine apart and pay $800 bucks endeavor. A pair of them (OEM) should only be about $70 for a pair online (Rock Auto, 1A Auto, Parts Geek, etc). Ford dealer or online will charge about $70-80 per piece.


The 2006 F150’s with the 4.6l engine don’t have variable cam timing.


———————————————
The fool hath said in his heart, There is no God. Psalm 14:1
 
Posts: 4053 | Location: Northeast Georgia | Registered: November 18, 2017Reply With QuoteReport This Post
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Picture of J387
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I have no actual experience with your engine but I would suggest checking for a clogged fuel filter (if equipped) or catalytic converter.



Even the Losers Get Lucky Sometimes
 
Posts: 411 | Location: Georgia | Registered: December 19, 2009Reply With QuoteReport This Post
We gonna get some
oojima in this house!
Picture of smithnsig
posted Hide Post
Clean the throttle body. It’s easy. Look it upon YouTube. I used to have one and this did it after replacing everything.


-----------------------------------------------------------
TCB all the time...
 
Posts: 6501 | Location: Cantonment/Perdido Key, Florida | Registered: September 28, 2009Reply With QuoteReport This Post
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Picture of ibexsig
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Long shot here....I just had acceleration issues with my Ford ranger and after changing a lot of the parts you mentioned i finally figured out that it was the A.C. System was low on Freon and the compressor was causing the engine to surge. If you run your air system in defrost mode it.might be a cause.
 
Posts: 319 | Location: NE Wisconsin | Registered: January 26, 2012Reply With QuoteReport This Post
"Member"
Picture of cas
posted Hide Post
quote:
Originally posted by smithnsig:
Clean the throttle body. It’s easy. Look it upon YouTube. I used to have one and this did it after replacing everything.


Any time I have any issue, the first thing I do is get some carb cleaner and spray the heck out of and around the butterfly in the intake. I had a car with "stumbling" issues years ago and a mechanic friend told me to do that. (over the phone, he'd never seen the car) I did and it went away. Something so simple. In the decades since, it cured a problem a second time. Now I do it as a matter of routine maintenance.


_____________________________________________________
Sliced bread, the greatest thing since the 1911.

 
Posts: 21529 | Location: 18th & Fairfax  | Registered: May 17, 2003Reply With QuoteReport This Post
Gimp with
The Limp
Picture of RBeach
posted Hide Post
quote:
Originally posted by smithnsig:
Clean the throttle body. It’s easy. Look it upon YouTube. I used to have one and this did it after replacing everything.


I did this when I changed the throttle body gasket. Cleaned throttle body to like new condition when I had it off, and cleaned inside intake as far as I could.


RBeach
_________________________________
What if there were no hypothetical questions? - George Carlin
 
Posts: 2104 | Location: Fort Mill, SC | Registered: June 12, 2005Reply With QuoteReport This Post
Gimp with
The Limp
Picture of RBeach
posted Hide Post
quote:
Originally posted by ibexsig:
Long shot here....I just had acceleration issues with my Ford ranger and after changing a lot of the parts you mentioned i finally figured out that it was the A.C. System was low on Freon and the compressor was causing the engine to surge. If you run your air system in defrost mode it.might be a cause.


Freon is good. System was checked this past Summer. Plus, system is turned completely off most of the time.


RBeach
_________________________________
What if there were no hypothetical questions? - George Carlin
 
Posts: 2104 | Location: Fort Mill, SC | Registered: June 12, 2005Reply With QuoteReport This Post
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Picture of 4MUL8R
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Having once designed Ford EGR valves, from 1984-1992, I can tell you that Ford went to a lot of trouble to prevent carbon deposits in the valve to cause it to either stick closed or leak.

It sounds like the problem occurs when you go "closed loop" as you mention after it is warm, the problem is evident. Before closed loop condition is reached, the A/F ratio is richer, and runs this way to prevent stumbling when cold.

If the EGR valve diaphragm is cracked, it would be a continuing source of a vacuum leak, if vacuum is requested by the controlling solenoid. But, it would not be opening the valve either.

If for whatever reason a carbon crust in the body of the valve is holding the pintle off its seat, the recirculation of exhaust gas can reduce the available oxygen for combustion, as it has already been combusted and has a bunch of vile chemical compounds in it (HC, NOx). This might be the cause of a sag in power.

The gasket back then was a carbon-coated thin sliver of metal that approximates a utility knife blade. Be careful.

For many years, all Ford engines had EGR. Then, advances in pollution control meant that only California engines had them. Not sure if yours has one or not, but it may not be fun to take off the supply pipe to the valve body. It is kind of like a plumbing fitting with a rotating nut surrounding a flanged pipe that seals against the valve inlet internal flange.


-------
Trying to simplify my life...
 
Posts: 5284 | Location: Commonwealth of Virginia | Registered: January 15, 2007Reply With QuoteReport This Post
On the wrong side of
the Mobius strip
Picture of Patrick-SP2022
posted Hide Post
quote:
Originally posted by 4MUL8R:
Having once designed Ford EGR valves, from 1984-1992, I can tell you that Ford went to a lot of trouble to prevent carbon deposits in the valve to cause it to either stick closed or leak.


Interesting.
When I was in the car repair business, I gained a lot of experience diagnosing Ford EEC-IV driveability issues.
EGR and EVP fault codes and problems were pretty common, particularly on earlier models.

Some aftermarket company even came up with an EGR valve gasket with a screen built in to prevent carbon chunks from jamming the valve partially open.




 
Posts: 4178 | Location: Texas | Registered: April 16, 2012Reply With QuoteReport This Post
Gimp with
The Limp
Picture of RBeach
posted Hide Post
Replacing the EGR did not solve the issue.

I added fuel injector cleaner and Heet and changed fuel filter again out of curiosity. With all of this done, the stumble is not as bad (very minor), but it is idling like a muscle car with an oversized cam.


RBeach
_________________________________
What if there were no hypothetical questions? - George Carlin
 
Posts: 2104 | Location: Fort Mill, SC | Registered: June 12, 2005Reply With QuoteReport This Post
Gimp with
The Limp
Picture of RBeach
posted Hide Post
quote:
Originally posted by Shifferbrains:
Since you have the Maximus, graph the MAF, both upstream O2's, and if you can both ST Fuel trims. Drive the truck, and from a stop take off smoothly to WOT and watch the graphs. The MAF, O2's and fuel trims should go high, pretty much mirror each other.


I did that and took 2 short videos of the screen with my phone, but I cannot upload them.

The MAF started in the high range at idle (5.11 with a 2-6 g/s range). As soon as I gave it gas, it shot through the roof, maxing out at 187 at WOT.


RBeach
_________________________________
What if there were no hypothetical questions? - George Carlin
 
Posts: 2104 | Location: Fort Mill, SC | Registered: June 12, 2005Reply With QuoteReport This Post
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