I just cleaned the IAC valve on my truck, still makes that stupid whirling sound under semi-hard throttle. Do I need to replace it or what? When off the engine it rattles if you shake it. Is that normal? If I do need to replace it how much are they?

I cleaned my TB while I was in the area, somewhat dirty. Also, what kind of funky socket does one need to remove the mass airflow sensor? I thought I had lots of tools but I had nothing to remove those screws with a point in the middle of them.

 

You can get tamper resistant Torx bits with a hole in the center to clear the pin.

 

It should *not* rattle when in your hand. I'd replace it.

Rich

 

Check all of your hoses too. We had the same problem with my bro's F-150 and thought it was the IAC. Well we took it to a shop and the guy took a water bottle that put out a tone of water mist. The vaccum leak sucked in the water vapor/mist and lead him right to the source. It was a split hose.

I thought it was pretty cool.

 

+1 on the special torx bit...I was fortunate to have a friend with it for his Ford, but it turns out my MAF was not the problem...

What kind of "whirring" noise is it? Long, short, in bursts, idle funny for a short while? Loud, soft hum? Have you checked for vacuum leaks? I replaced a hose 2 weeks ago for a "whirring" problem as well. Are all the bolts tightened correctly? Depending on the idling and humming, it could be a bad head gasket? Are you sure it's from the engine, and not an accessory?

 

FWIW, I cut a slit in the heads of the MAF torx screws with a Dremel so that they could be removed with a regular screwdriver. After cleaning the unit, I replaced the old screws with new phillips heads screws. Now whenever I want to access the MAF sensor I don't have to fiddle with special torx head sockets. This has been done on all my Fords.

 

Thanks for the help guys. I've seen hollow torx bits before, just don't own any yet. From what I have researched, the whirling noise must be a bad IAC, I hope. It only does it at certain RPM's, about half throttle during acceleration. Other then that she runs like a top.

How much cabbage will I need to get a new IAC? Thanks again.

 

$75-85.....I just replaced mine Thursday. $76 at Auto Zone.

 

Priced a new one today while at Ford store for re-call. $65. Going to get one, tech. said mine was bad.

 

Wow, not bad. Ford wanted $95 here for it.

Since replacing my IAC, I have noticed a decent improvement in idle, acceleration, and mpg. Not to mention it doesn't cut off every time I put the truck in park now. I also noticed it lowered my idle rpm to about 700. Seems kinda low to me, but the truck stays running, and my alt seems to be handling it ok. Not sure how it'll do this winter with wipers, heat, lights, etc running at the same time, though. I might have to bump up my idle a little bit. Haven't done any "real" testing on mileage yet, but so far, it seems to be giving me back about 3 mpg.

 

Hope it helps my MPG. I used to get 18-19, now only 16-17. I hate getting half-ton mileage with V-6 power.

 

The best I ever got stock was 19 with 100% highway miles. I usually drive about 50/50 , and got about 16-17 (when it was new). It slowly went down to about 17 highway, and 14 doing 50/50. When I put the Bama 89 torque tune, cat-back system, and new plugs/wires on it at about 50k (I got just over 90k on it now), it got me back up to about what I got when the truck was new.

Over the past few months, I've noticed my mileage drop again to around 16-17 highway. Since I changed the IAC, I've run 3 tanks through it on the 89 torque program. I got 19.5 & 20.5 on 2 tanks at about 75% highway, and 18 with 50/50. Since then, I've switched to the 93 torque program to see how that does. Haven't been through a full tank yet, but after I run a few through it, I'll post back to see if there's any real difference now.

If I can keep it at 20 highway, and 18 50/50, I'll be a VERY happy man.