I am having a problem with the idle on my 04 F150. When it is in drive at a stoplight it is idling at about 600-700Rpms which is a little rough but not too bad. If I shift into park it drops down to about 300 and then goes back up to 600-700. Occasionaly it will die when it drops down to the 300 but not always.

This started happening after I replaced the battery so I disconnected it for 2 hours to reset the computer. low and behold it fixed the problem for about a week or so but now it is back.

Anyone have any idea what could be going on with it. I have 60K miles on it.

Clean the throttle body with some throttle body cleaner. Remove the air tube into the TB and clean the throttle plate and use a screwdriver to open the butterfly and clean the top and bottom of the body and the throttle butterfly. Make sure you use a TB cleaner, and not carb cleaner, as it will dissolve the special coating on the TB from the factory.

Clean the mass air flow sensor with Electronics parts cleaner or MAF cleaner. DO NOT TOUCH THE MAF. Let it air dry (should be instant). Put a can of Chemtool in the gas tank.

Is this a 4.6L or 5.4L When was the last time the fuel filter was changed? Assuming you checked the air filter and it was clean (no dead birds in the airbox etc).....

if this still continues after the MAF and TB cleaning and a fuel filter, it may be time for a IAC Valve.

[This message has been edited by 1agswitchin4lanes (edited 2/23/2010 1:39p).]

Is Chemtool similar to Seafoam? I dumped a can of that in there after the problem started happening to see if it would take care of the problem (obviously it did not).

This is a 5.4L and the fuel filter has not been replaced since around 30K miles so I will replace that as well. The air filter was just replaced so I can rule that out.

Is the IAC Valve a do it yourself job?

Chemtool is similar to SF.

IAC shouldnt be too bad.

I'd try the MAF and TB cleaning first.

my 2005 4.6l f150 has had a slightly rough idle since day one, is there anything that can be done about it? is a good tb cleaning about all i can do? two different dealers looked at it when it was under warranty and could come up with no solutions.

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my 2005 4.6l f150 has had a slightly rough idle since day one, is there anything that can be done about it? is a good tb cleaning about all i can do? two different dealers looked at it when it was under warranty and could come up with no solutions.

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Really? Usually its the 5.4L That has that issue. Clean the TB and pull the KAM fuse, let the truck relearn the idle process.

There may also be a new software revision out with updated software too.

1agswitchin4lanes - I don't know how far your knowledge of the 04 F150 extends but I also have an issue with the anti slip differential where it causes the whole truck to shutter when I take off from a stop with a slight (or full turn) of the wheel.

Do you know anything about that problem. I think I read somewhere that there was a defect in the 04s but Ford was not covering it unless the truck is still under warranty.

Thanks for all of your input

Yes.

Change the fluid and add the correct friction modifier.

If it doesnt go away, you'll need to replace the clutch packs in the differential, or add an additional pack in to quell the shuddering.

@brush99

If you have a two-piece drive shaft, there may be a TSB on the Carrier bearing.

[This message has been edited by DakotaAg01 (edited 2/23/2010 4:15p).]

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I don't know how far your knowledge of the 04 F150 extends

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about as far as peter north, i'd say

sts7049 - Nice reference!

I have read that the clutch packs are defective in the 04 model and that it is at least an $800 job to replace them. If I were to just replace the fluid and add in the friction modifier (assuming it did not fix the problem) would that be enough to not cause more damage going forward. I should mention that it has done this shudder from day one but it is definately worse now.

Is the only way to drain the rear differential by removing the plate or is there a plug that can be removed like motor oil? What does a service like this run at a shop?

brush99,

I'm having the same issue on the wife's 02 Explorer. We had the shop change the fluid with Motorcraft and add the fric modifier. I want to say it ran around $150 or so. I could be wrong.

It didn't make a difference for us. I've called around a few places and to have the clutch packs replaced you're looking at 900-1k. For that much I'm just going to deal with it. From talking to 1Ags I believe it will not cause a problem, it's just annoying.

I was also told by a shop that often times after you change the clutch packs the rear end will start to whine and you have to get the rear end replaced. Could have been an upsell though. 1Ags, were they BS'ing me on that?

You guys need to call around to some transmission shops and maybe mustang speed shops to get quotes.

400 bucks would be a fair price to have this done.

If it is just going to be annoying and not do anymore damage then I will likely just deal with it (I have dealt with it for 6 years already)

Where is the IAC Valve on the 5.4L? I want to also try and clean that to take care of my idle problem.

Thanks

Oops. Realized that the 3 Valve 5.4L does not have an IAC. (Drive by wire)

Clean your TB.

Rear end shutter is clutch packs. Been there done that. Luckily it was still under warranty. Commmon issue on the 04s

Its been a while, but I think i had a similiar idling issue on my 04 and it had something to do with the variable cam timing and cam phasers. It was not cheap to repair. I would start with cleaning the MAF, as others have suggested.

1Ags,

You talking about just replacing the clutch pack(s) or having the rear end rebuilt/replaced?

Is it true that they will start to whine after replacing the clutch pack?

Not if you know what you're doing.

And yes, that should be the price parts and labor for new clutch packs, S Spring and fluid, modifier and gasket.

I read something interesting in the manual today. It said that whenever you disconnect your battery or replace it that you should do the following so that the computer can relearn the idle process:

1) turn off all auxillary systems
2) start and let it get up to temperature
3) idle for 1 min
4) turn on A/C and idle for 1 more minute.
5) take it for drive (possibly up to 10 miles)

It says that failure to do that can cause rough idiling. This makes sense because the problem started after I replaced the battery. When I disconnected it again to reset the computer it made the problem go away for about a week but I definately DID NOT go through the idle process outlined above.

I need to clean the TB and MAF and replace the fuel filter anyways so I will do that and then try the disconnect process again.

YEs. The OBD-2 relearn process is very important.

when it says "let the engine get up to temperature" ~ how long does that take?

to me that means - let it warm up to where the temp gauge normally rests when warm

That is what I thought as well but, the next step is idle for 1 min which you would have already been doing for the last 5-10 min to get up to temperature.

true, but that's the guidance.

1agswitchin4lanes - Do you have a shop somewhere in H-town? If so where are you located?

Fleet only. Sorry.

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Clean the TB and pull the KAM fuse, let the truck relearn the idle process.

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tb has been cleaned, fuel filter replaced. idle is smooth for now, will try the kam fuse and idle relearn if shakes return.

thank you 1ag

you're very welcome!