vacuum leak

[Hamfisted]

Do you know what brand was used, and make sure the gasket is in good shape.

 

[91fox]

I checked the throttle body, and it was pretty clean however I cleaned it further, the iac I can't remember the brand... However, when I look on rockauto I see a split in the year? I'm not sure if something in the solenoid was changed or what, however, I can't confirm or deny if I have the correct iac or not ..

 

[Hamfisted]

I use a old toothbrush and solvent to scrub the throttle body. Make sure the sealing edges of the butterfly are clean.
Can you take a look at the door sticker on your Expy and see if it was manufactured before December of 2002 or after?
Looks like the mating surface on an actual Motorcraft IAC is beefier or more surface area than what you have there. Although several brands are beefier than that.
You don't need sealant in addition to the gasket when re-installing the IAC, the gasket alone is all you need.

 

[91fox]

The truck was built in may of 03,that's why I'm questioning if I got the correct iac considering all the mfg make them look different and the casting apparently has no correlation to the year.

 

[Hamfisted]

That's interesting. You have to go to the 2004 model year at Rock Auto to get the correct part number in Motorcraft.

2L1Z-9F715-CA


Did your idle speed issue start just after installing this new IAC you currently have ? Do you still have the original IAC ? (If it was original?)

 

[91fox]

the original was discarded, i ending up putting an engine in this truck with 50k on it. I re-sealed the entire engine and put on a lot of new parts to try to thwart any potential issues. This however, didn't happen, but, I'm down to the weird idle being the only known at problem this point. I might try a different IAC just to see how it behaves.



EDIT: I just ordered a ford iac from amazon, hopefully that will fix my last issue. Just have to wait for it to show up

 

[Hamfisted]

Sounds good. They don't normally come with a gasket. So unless you already have an extra one laying around pickup one of those too. Just use the gasket by itself, no extra sealant.

 

[91fox]

Alright, so I got the motorcraft IAC in today, and replaced it along with a new gasket. Started the engine up and let it run. I couldn't get it to reproduce the same engine stumble condition when coming back down to idle speed. So, I'm hoping that this may have done the trick, however, time will tell. Thanks again ham and everyone else whose helped out!