Hey guys looking for some troubleshooting help first off not sure if I'm posting in the right area I hope I am it has to do with my ex

2005 Excursion v10 137000 miles I am experiencing a rough idle only after the truck has been idling for a while 5+ min or so. On cold start warm start dosnt make a difference truck runs perfectly until it's been idling for a few min then starts a lopeing idle tach drops down to around 4-500 rpm motor sounds almost like a mis fire I can press on the gas and it sputters up until it's running over 1200 rpm then smooths out and runs perfectly until it's allowed to idle for a few min then just repeats no codes are present no check engine light at all

I changed out plugs and coil packs at 100000 miles roughly year and a half ago (motorcraft parts) problem started just recently I have double checked all connections are good at plugs and at fuel injectors from what I've read up on from this forum it sounds like I could be experiencing an IAC issue or possibly an EGR issue I have checked all the rubber hoses associated with both systems and all are in good shape hold vacuume as they should are there any tests that I could perform on the IAC or the EGR to determine if it's one of those I'm trying to avoid throwing parts at it if possible, or is there anything else that I should be checking oh also cleaned the mass air flow a few days ago no changes

As always any help or advice is greatly appreciated

 

A dirty or clogged IAC valve could cause those symptoms, I would pull and clean that first, it's free and pretty easy.



Unrelated to your current issue I'm surprised to read that your '05 V-10 has an EGR system. I thought Ford had pretty much done away with them by '05 and was using the PCM tune to meet the emission goals. My '05 Cali spec V-10 does not have an EGR, is your rig a Cali emission model or 49 state? Just curious.

 

From your description it sounds exactly like an issue I had on my previous ex, in my case it was the IAC valve.

 

You can run seafoam through the brake booster line while idling and see if that helps clear it up.

Similar to what this guy did. If it works your IACV is likely filled with Carbon.

 

double post

 

It might not I couldn't find any obvious lines from the manifold but there is a metal line that comes up from the back of the motor that turns into a rubber line and plugs into a disk shaped object on the right side of the motor I just assumed it was EGR (making myself look dumb) I will try and clean the IAC and report back thanks

 

Not dumb, just learning!
Take a look at the driver's side exhaust manifold, there will be a raised boss between the second and third cylinder's outlets. If that boss is a solid blank (like mine in the picture below) then you do not have an EGR, if you do have an EGR that is where the metal tube will tie into the manifold.

 

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Yes mine looks like yours so I don't have EGR well that rules out one possible problem see troubleshooting at its finest! I'm not much of a mechanic I'm one hell of a parts changer I can tear anything apart and fix it I just don't always know where to start looking for the problem that's why I spend countless hours reading up here you guys are a wealth of knowledge! I will try cleaning up that IAC the next day or two depending on my time line and report back my findings

 

Good luck, and yes please do report back!

 

Our 2002 Cali spec V-10 does not have an EGR.

 

That disk shaped object on the passenger side is the Evap Service Port.
I read on another forum you can take off the green cap and connect a smoke machine to pressurize the system and check for leaks.

 

Update....

Ok so I pulled the vacuum lines to the IAC rinsed with sea foam and wiped out as best I could they were not that dirty there was a minor restriction in the plastic section of the vacuum line but nothing to major, pulled the throttle body cleaned up wasn't to bad it's got some miles on it but I've seen worse pulled the IAC cleaned out and wiped out as best I could it was dirty but not anything I would consider detrimental put it all back together while I was working on it I noticed that the gromet on the wire loom for the mass airflow was partially unseated from the air box so pulled it out wiped it all out and reinstalled.

It's been roughly 24 hours and I have not had anything out of the ordinary trucks been running smooth and strong no idle stumbles or high idle symptoms. My dad (white collar ford employee not sure what he does for ford but I know he works with Lincoln) sent me work packets on the IAC and ERG per my request a week ago.... I read thru the IAC packet and it mentioned in step #1 to ensure that there is no restriction and or loss of vacuum from the IAC to the air filter. So I think that the IAC is fine on the truck and it was just acting up due to the vacuum supply restrictions found and possibly a little bit of loss due to the gromet in the mass air flow not being seated properly.

I'm calling this fixed thanks for all the tips advice and input guys saved me some headaches and kept my pennies in my pocket! YOU GUYS ARE AMAZING!!

 

WE3ZS sorry I missed this earlier my EX is not Cali spec thanks again for the help

 

Glad to hear that you got it all smoothed out!