5.4 Rough Idle
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5.4 Rough Idle
I am still having some rough idle issues with my 2001 F-150, 5.4 L. THis site has been a great help and I hope someone can head me in the right direction.
On really cold mornings, after I warm up the truck and drive a mile or two, it will either have a very rough idle or die at a stop light. I need to put it in N and gas it up to keep it from dying. After I stop for a short while for coffee, etc. it has no issues with idling - the problem goes away!
After the first CEL (P0401), I cleaned the MAF, replaced the PCV, changed the air filter and cleaned the IGR. The codes were gone and I was ok for about a day or two.
It started up again, CEL is a P0171. I replaced the IAC and checked the DPFE (it was ok). Still having the same problems. The plugs were changed about 20k miles ago (there is 110k on the truck).
(This same thing happened last winter, but the dealer siad nothing was wrong - it only happens when I first start off in the morning and it must be very cold - so they couldn't get it to repeat.)
Any advice is much appreciated!
On really cold mornings, after I warm up the truck and drive a mile or two, it will either have a very rough idle or die at a stop light. I need to put it in N and gas it up to keep it from dying. After I stop for a short while for coffee, etc. it has no issues with idling - the problem goes away!
After the first CEL (P0401), I cleaned the MAF, replaced the PCV, changed the air filter and cleaned the IGR. The codes were gone and I was ok for about a day or two.
It started up again, CEL is a P0171. I replaced the IAC and checked the DPFE (it was ok). Still having the same problems. The plugs were changed about 20k miles ago (there is 110k on the truck).
(This same thing happened last winter, but the dealer siad nothing was wrong - it only happens when I first start off in the morning and it must be very cold - so they couldn't get it to repeat.)
Any advice is much appreciated!
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Intake manifold gasket? When your truck heats up the manifold expands and "seals" the leak you have between the intake and the block. It could be a small leak which is why you only experience it on really cold days.
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From: Where the war is...
The stuff I did in described in this post (link below) cured my rough idle. I am thinking you may have a stuck EGR valve and some vacuum leaks, I had several leaks (8 years of rotting and cracking rubber hoses) and replaced those components during a throttle body removal, cleaning, and overhaul. Some ideas are listed here: https://www.ford-trucks.com/forums/8...-a-5-4-2v.html
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I thought about the vac leak - this would seem very appearant as the engine heats up the leak seals itself. Funny thing, though, the engine is warm when I leave and it still happens. The issue continues until I stop and leave it alone for a bit, then drive off.
(I did think dirty injectors and put the additive in. As far as condensation in the tank, I think it would happen all of the time instead of just when it's cold?)
I'll take a look at the vac leak again, the TB removal/clean will probably be the next step.
(I did think dirty injectors and put the additive in. As far as condensation in the tank, I think it would happen all of the time instead of just when it's cold?)
I'll take a look at the vac leak again, the TB removal/clean will probably be the next step.
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From: Where the war is...
Sounds like your EGR is functioning, but it might still have a bunch of carbon in the passages or even a potential leak in the gasket. In addition to all of the hoses that attach to that throttle body and intake adapter elbow, there are at least four gaskets that I know of that could have a slight leak (throttle body-to-adapter gasket, adapter-to-intake gasket (which is an o-ring), IAC-to-adapter gasket, and EGR-to-adapter gasket). In my case, all except the IAC-to-adapter gaskets were wearing in one small spot or another. And that evaporative return hose that connects the evap management valve to the top of the intake was practically falling appart in my hand, a huge leak source, I just replaced that directly. Give those things a look see.
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From: Vale, NC
I thought about the vac leak - this would seem very appearant as the engine heats up the leak seals itself. Funny thing, though, the engine is warm when I leave and it still happens. The issue continues until I stop and leave it alone for a bit, then drive off.
(I did think dirty injectors and put the additive in. As far as condensation in the tank, I think it would happen all of the time instead of just when it's cold?)
I'll take a look at the vac leak again, the TB removal/clean will probably be the next step.
(I did think dirty injectors and put the additive in. As far as condensation in the tank, I think it would happen all of the time instead of just when it's cold?)
I'll take a look at the vac leak again, the TB removal/clean will probably be the next step.
That's why I was thinking fuel filter. If there was some water in there it might separate and get out of the way when cold, like an ice cube floating? Then when it gets warm you start to experience problems.
I know I probably sound like an ad for seafoam, but it has always worked well for me in a variety of engines. Might be worth a shot.
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I have already changed the EGR and IAC gaskets when I cleaned/replaced them and they looked solid, so I think the leak check will need to be next on a cold morning.
I felt around the majority of the other hoses and they all seemed to be in good shape.
I felt around the majority of the other hoses and they all seemed to be in good shape.
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clm2012
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Jun 8, 2014 07:27 AM
