I'm looking for some direction on where to start my troubleshooting.

First off, it is a 2001 F-250 auto trans, 4x4 crew cab with 99,000 miles by the original owner (me).

Over the past month or so on initial (cold) startup the idle drops down to around 5-600 RPMs and dies. If I keep the idle up around 1,000 manually for about a minute or two, it will drop down to the 5-600 RPM range when I take my foot off the throttle, but continue to run.

The motor runs fine and doesn't miss, it just idles a bit low. I've had it checked several times with no codes showing. Up until now (11 years), on initial startup it would idle up to just over 1,000 RPMs and slowly drop down to around 7-800 as it warmed up.

I imagine it is something simple, but I don't know where to start. Any suggestions? Thanks for the help.

Edmo

 

Mine did that once....used a bottle of Seafoam in the tank which was about 1/2 full.....back and forth to work once(approx. 36 miles)....ran great afterwards.

 

IAC - Idle Air Control - known to stick on these engines. Replace it.

CPaulsen, I'm willing to bet your IAC stuck once, and the Seafoam wasn't the reason it went away

 

Thanks for the replies...

Any thoughts on trying to clean the IAC first with carb/throttle body cleaner? Is that even worth a try?

Edmo

 

Yes and no, ive heard of mixed results, just replace to save hassle.

 

Ditto. I don't think it's really an issue of the valve itself sticking from dirt, it's more likely the servo/motor that moves the valve. The air supply to the IAC is right off the main air intake after the air filter, so it doesn't get much dirt or PCV gasses, if any. The one in my '97 Cougar was nice and clean, just sticky so I just replaced it - been fine since.

 

I've got an 88' 5.0L, it's been running rough and will barely stay running on start up. I will definitely be changing the IAC valve out; any recommendations on a brand? Advance Auto has BWD, Delphi and Wells Vehicle Electronics. I've only heard of Delphi, may look at a few different stores as well.

 

You boys were "spot on" with your troubleshooting...

New IAC installed and she purrs like a V10 kitten.

Thanks much!!

Edmo

 

My 05 E350 V10 van shows some idle problems, and not very often, but when it does it usually involves getting on the brake and doing a turn. So I am considering changing mine.

I have looked on Advance Auto's website and they show a wide variety of IACs and a wide variety of costs.

Any pointers?

 

Pointers? For my Excursion, it was to clone myself and use my clone's 5 year old hands to get back in there to swap it out, lol.

On van I'm guessing you can access it from inside? If so, tips I can provide from my recent swap:
...the bolts that hold it to the intake are WAY too long...you'll be spinning that socket for a long time, then it falls out...if it does, it will drop into the openings in the intake manifold and be lost forever.
...my gasket came off half on the idle air control and half on the intake. If your gasket self-destructs, use a shop vac if you can get at it from the back of the motor if you can't recover the entire gasket. I had to do that to make sure when I scraped off the remains from the intake that none fell inside.
...in my case, they didn't have a replacement gasket, so I had to make my own using the "roll of gasket type material" they sell. Not the cork stuff, this is heavier than tar paper without the tar. Be careful you cut out clean holes for the bolts...any of that gasket material gets inside the hole it will make tightening the bolts VERY hard to do.

 

I would clean the Throttle body with a rag and some Berryman ChemTool.....

 

This thread was last updated over EIGHT YEARS ago!

Cleaning the throttle body is a good idea in general but I've found removing it completely, scrubbing with a toothbrush or something similar along with dedicated throttle body cleaner does a more thorough job. Be careful of any electrical connectors as those grow fragile over time, easy to break the locking tabs etc.