[bkenobi]

My 2006 Escape Limited 3.0L drives fine but when I stop at a stop light for instance the engine idles very high. I initially thought it was an accessory like A/C but with everything off it still does it. If I put it into neutral or park it drops to a normal idle. Looking online it looks like this could be either a fuse, a leaking vacuum hose, or the idle air control valve.

I pulled the IAC and it did not look all that dirty but I cleaned anyway. I tested on the bench by applying 12V to the solenoid and the valve actuates, but it doesn't open very much. It pops open to most of the throw but then settles at a barely cracked position. None of the local stores have the part in stock or else I'd have picked on up to see how far it should open new.

Is there anything else that I should look for? I was thinking I should spray starter fluid or carb cleaner when running to see if I can locate a vacuum leak. I didn't see any fuses that were blown. Any thoughts?

 

[Mountain Escape]

My 2006 Escape Limited 3.0L drives fine but when I stop at a stop light for instance the engine idles very high. I initially thought it was an accessory like A/C but with everything off it still does it. If I put it into neutral or park it drops to a normal idle. Looking online it looks like this could be either a fuse, a leaking vacuum hose, or the idle air control valve.

I pulled the IAC and it did not look all that dirty but I cleaned anyway. I tested on the bench by applying 12V to the solenoid and the valve actuates, but it doesn't open very much. It pops open to most of the throw but then settles at a barely cracked position. None of the local stores have the part in stock or else I'd have picked on up to see how far it should open new.

Is there anything else that I should look for? I was thinking I should spray starter fluid or carb cleaner when running to see if I can locate a vacuum leak. I didn't see any fuses that were blown. Any thoughts?

I would use carb cleaner, not starting fluid
Often times you can hear a vacuum leak as a whistle, or whooshing sound
I believe that the fact that putting it into neutral or park stops the racing of the engine is pertinent.
Do you have a code reader?
I would see if you can duplicate what is going on while parked in the driveway, and the hood up.
that the idle valve seems to check out OK on the bench, have you checked for continuity in the plug wiring?

if you get/have a ForScan, you can check values while idling, while driving, etc

 

[bkenobi]

I would use carb cleaner, not starting fluid
Often times you can hear a vacuum leak as a whistle, or whooshing sound
I believe that the fact that putting it into neutral or park stops the racing of the engine is pertinent.
Do you have a code reader?
I would see if you can duplicate what is going on while parked in the driveway, and the hood up.
that the idle valve seems to check out OK on the bench, have you checked for continuity in the plug wiring?

if you get/have a ForScan, you can check values while idling, while driving, etc

Yes I have a bluetooth scanner so I can run torque while driving. I don't see any codes but it is repeatable. It seems more prevalent when it's cold. I wasn't sure I could see the IAC command or any related air flow rates on the scanner but can check what is available.

I sprayed the remainder of my carb cleaner on all the hoses that looked like they could be vacuum related and didn't notice anything changing the RPM but it's possible I didn't get everything.

 

[tomw]

When you start a cold engine, the rpms should be above 1k. Close to about 1200 rpms. After a short while, the rpms should start dropping in steps. Within 3 minutes, roughly, the rpms should drop to about 750 in neutral/park. If the IAC does not do that then it is likely dirty/sticky/???. When you put the selector in D or R, the rpms should stay stable @750. Turn on the A/C, and it should stay stable. If not, it is possible the IAC is not working.
I do not think they can be tested by applying 12VDC. The are 'pulsed' with DC voltage to make them move as I understand.
I would look at a boneyard for one that could be fitted if the above tests indicate the IAC is not working properly. Sometimes you can clean them, and they will work for a while, sometimes even cleaning does not work.
The air that goes to the IAC goes through a side passage visible with the air cleaner tube removed. The passage should be clear of debris or insect products. If you remove the IAC you should be able to blow air through the passage readily.
tom

 

[bkenobi]

Thanks for the description of the proper function. I will test again after work. Last night after reinstalling post cleaning the Escape seemed to be idling very low. Since the only thing I touched was the IAC I'm heavily leaning towards that being the issue. Perhaps sticking one way and now the other?

Do junk yard parts offer reliable service? I called around and local parts stores can order next day but the price is up to $100. I recall changing one several years back for closer to $30. Crazy!

 

[ancientmariner]

$32.79 at Rock Auto :

2005 MERCURY MARINER 3.0L V6 Idle Air Control (IAC) Valve | RockAuto

RockAuto ships auto parts and body parts from over 300 manufacturers to customers' doors worldwide, all at warehouse prices. Easy to use parts catalog.

www.rockauto.com

 

[bkenobi]

I replaced the IAC even though it seemed to be functioning correctly since it was fairly cheap. I sourced an OEM from ebay for around the same price though I imagine aftermarket would have been fine. After a couple weeks, the issue seems pretty much unchanged. I looked around online for anything that could cause idle vibration without tripping codes and didn't see much.

It looked like the throttle body could have gunk keeping the valve from sealing so I removed the air line. I started to remove the throttle body but when I saw it had coolant lines running through it, I decided to clean in place. The valve was pretty clean anyway so I can't see that being an issue.

I cleaned the MAF while things were disassembled but it was also really clean to begin with. The air filter was changed recently so that's not an issue.

I also read that the EGR could get stuck closed which would cause poor idle but not trip a code. Stuck open would trip a code but would also prevent the engine from starting well (lower than designed idle). I pulled the EGR and it looked ok. It had a little carbon inside, but nothing major. I don't have a vacuum pump to test it, so I simply put throttle body cleaner in one side of the EGR and sucked on the vacuum line. The fluid held in the upper chamber until actuated and closed when released. So, the EGR was good but is now cleaner. The upstream and downstream tubes looked ok but I cleaned with a brass pipe cleaner anyway. The engine still idles pretty rough.

The last thing I have found that could cause this is a faulty front motor mount. One video suggested starting the vehicle and getting it so it vibrates, so I had my helper put it in gear with engine running. I next used a jack to remove a little load from the engine on the vehicle. The vibration stopped suggesting (by the video) that the mount was bad. Does that seem like a valid test? I can either replace or have replaced the front mount if that's the next step.

Alternately, is it a known issue where these SUV's just run with a higher vibration when idling? If so, I'll stop chasing down a design flaw as though it's a broken part.