Ok, I had Ford change the IAC. It took them about 40 minutes to do the job and my rig now starts up just fine, rpm's don't drop anymore and idles great. The old IAC was very dirty inside. I didn't like paying the $125. but my hands are clean and I didn't spend all Saturday trying to get to two bolts.

I'd say, Great call!!!! Many thanks for pointing me in the right direction.

now moving to the next little issue.....

A few weeks ago, and also while I had the idle issue at start up, I would also hear a double thump right after the engine starts, like thump thump. It kind of sounds like the heater core or AC, but I don't think that is it. I was going to wait and see if it did it after the IAC change out, and it does. It won't do it all the time, but sometimes, more when it's cold, I will hear a double thump instantly after I start it. It then runs fine and you never hear the thump again. I tried turning off the AC, didn't matter.

Anyone have any idea what would cause this type of noise? A friend told me to check the cadilack converter?? How the hell do you check that??

I also have a K&N air filter that used to have a gasket on it, but it became too streched out and I stopped using it. The filter still filts stung inside, but I wonder if there is just a little play and the suction from the motor is causing it to slam in place and make a thumping noise???? I know, long stretch, but I'm trying to think of anything that could cause this.

It doesn't seem to be effecting the way it runs and there are no codes, etc. I just don't like new abnormal noises!

Thanks,

Steve

 

Maybe piston slap? Search the boards here and you'll find a lot of material to read. You might find that the symptoms describes are exactly like yours.

 

Check the bolts to make sure your starter isn't loose and getting batted around.

 

I bought two IDA from Advance and I am still having the same problem. High idle when im driving, it will jump into a high idle and lunge for word. Should I buy one form ford??

 

That depends on what an IDA is?

 

Just replaced the IAC on my 2000 Expedition; didn't bother cleaning since the part wasn't too expensive. This post was very helpful. A couple of things I did to that can make the job easier. First, one of the heater hoses is realy in the way. I already had the hose splice to add in a fitting to back flush so I was able to disconnect and move the hose out of the way. Cutting and splicing this hose back in with a fitting would be worth the effort. Be prepared for about a pint of coolant to leak at when cut. Second, I was able to push the IAC back along the firewall to the diriver's side making it much easier to get the connector off.

 

One thing to watch out for if doing this to the heater hose, is to not let the coolant spill down into any spark plug wells. You could end up with a misfire afterwards.

 

I cleaned the IAC on my 99 Expedition following the directions in this thread. The only thing I did differently was buy a 8mm gear wrench to make it easier to remove the lower bolt. I am not a car guy like some of you, but I was able to do this myself with no cost other than the new wrench and the carb cleaner. Thanks for the post. You saved me money and the aggravation of dealing with a repair shop.

 

Excellent instructions and pictures! I just fixed my wife's 98 Expedition following the instructions in this article. I did it on my lunch break...took me 50 minutes with just standard 1/4 ratchet and sockets. Thanks so much for posting!

 

Thanks, 97ExpGuy, for creating these instructions. I just cleaned the valve on my 98 Expy with 122K miles. The valve was nasty looking; lots of black crud caking the spring. It seems to be idling better now. I'll know for sure when I take it to work early Monday morning. Getting the valve removed and installed is not quite as bad as I imagined it would be. I wouldn't have tackled it had I not read your post. Thanks, again!

It has been about 2 weeks since I cleaned the valve, and the truck is running great...smooth idle all the time, every time. Thanks again!

 

Hey my 2005 EXP EB has the IAC as posted in the picture by Jester.. Can that style be cleaned like the others?? Any advice greatly appreciated before it I take it apart.

 

These posts have been awesome. But I don't see how I could do this without dropping the bolts. I have a 98 as well, and my question is: How did you get your hands and a ratchet in there past the pcv vacuum lines and remove them without dropping the bolts? And how did you ratchet the bolts? What tools did you use? Did you remove the vacuum lines?

It doesn't appear to allow for positive ratcheting.

 

First thing to know is that in the Expy engine compartment, everything is a tight squeeze. All jobs are doable, it just requires patience and critical thinking.

I didn't use any special tools and don't worry about the vacuum lines. It is a bit of a tight squeeze but I didn't move anything out of the way. Just remove the plastic engine cover to give yourself more room (and leave it off IMO). To remove/replace the bolts, I used a 1/4" standard ratchet with an 8mm shallow socket. They might be a little tight, so be patient.

Once I got the bolts turning, I removed each bolt with my fingers - being careful not to drop anything. Once the bolts were removed, the IAC valve is free, pull it toward you so you can disconnect the plug from the wiring harness. To reinstall, start the bolts with your fingers. I had plenty of room to ratchet and get everything back and tightened up.

 

FYI, there is a gasket, so watch for it.

 

Yep, I realize that. I put that in my guide but the person asking the question I quoted didn't seem to think there was enough room to access the IAC with regular tools.