2004 4.0L Explorer Low Idle Problem

[mikeinri]

Hey guys,

I have a 2004 Explorer, 4.0L V6, about 170,000 miles. No CEL, but it idles extremely poorly. Hot or cold makes no difference. It idles so low that it's not turning the power steering pump fast enough, making parking a huge chore. Drives well otherwise.

I think this started around the time my battery died due to a faulty brake light switch. Not sure if that wiped out some memory or programming? It's been a month, so I doubt it's learning-related...

Searches here mainly point to dirty IAC, which this model year apparently does not have (per Haynes manual). I don't trust the local dealer not to screw me, and I don't know that my local garage can figure this out without a code.

I don't want to blindly part-swap or waste time chasing stuff.

Help!

Mike

 

[Dave8338]

Your 4.0L has an IAC valve.
Here is a link to Rock Auto for the best price:

http://www.rockauto.com/dbphp/mak,F...28E%29,Fuel%2FAir,6072,Idle+Air+Control+Valve

 

[mikeinri]

Where is that installed? I didn't see anything that looks like those.

Mime

 

[rmcknight]

clean the throttle body with carb cleaner, spray the heck out of it with the car running, varying the throttle. also clean the MAF (its in the air intake you just took off to get the the throttle body). also put in a new IAC, you cant clean that very well, as they fail internally.
if that doesnt work, change the plugs, then the wires.
then if still there, you may have a vac leak, but that should cause fast idle, but still may be there causing the computer issues. that requires you to remove the upper air intake and check the seals, they often fail and cause issues. then if you still have issues, you may need to pull off the lower air intake and check the seals on the bottom of that.

that should keep you out of trouble for a weekend.....

 

[mikeinri]

I recognize everything in your list, but don't see an IAC. Anyone have a pic of a 2004 showing the location of this part?

Anyone else think it's odd that there is no CEL (and presumably, no codes)?

Mkke

 

[rmcknight]

Is your 2004 drive by wire?

 

[rmcknight]

You have no IAC, 2004 year seems to be the switch to drive / fly-by-wire.
http://www.explorerforum.com/forums/showthread.php?t=253445

 

[mikeinri]

Yes it's drive by wire...

So, we're back to my original post. What's the likely cause of these symptoms on my drive-by-wire truck?

Mike

 

[D Hook]

Research what to spray to clean the throttle body. I've read (somewhere) that using carb cleaner can eat the coating on the metal. I know they make a specific throttle body spray cleaner. But you might want to do some research on it.

Cleaning the maf might help.

 

[chopperb]

Remove and clean the throttle body. Remove the neg battery cable for 10 min after you cleaned the throttle body. There is a tsb on this issue.

 

[chopperb]

Attached is the tsb that I use when I have these come into my shop with the same problem.

 

[mikeinri]

Great, thanks. Is there a way for a homeowner to confirm the PCM code version currently installed?

Is there a gasket that might be damaged when the TB is removed?

Mike

 

[rmcknight]

Great, thanks. Is there a way for a homeowner to confirm the PCM code version currently installed?

Is there a gasket that might be damaged when the TB is removed?

Mike

You don't remove the TB, just the air intake. And no gaskets at all unless you take it off, even then none get harmed.

 

[mikeinri]

OK. TSB says to remove the TB. If that's not necessary, so much the better.

Mike

 

[mikeinri]

OK, good news/ bad news...

Disconnected the battery. Took out the air box, MAF and TB (it all looked much easier to clean off of the truck). Cleaned the MAF with MAF cleaner (it actually looked fine when it came out). Cleaned the air box with carb cleaner (wishing now that I had just used soap and water). Cleaned the TB and its "gasket" with TB cleaner and a tooth brush (per YouTube videos).

Put it all back together, and it runs much, much better. Idle seems a bit low, but at least it isn't trying to stall, and the throttle responds much better now. I need a new air filter, forgot to get that ahead of time.

Anyway, the engine side of the throttle body plate and inside of the chamber was completed coated in carbon (soot). What would cause that?

The bad news is, my steering didn't improve. The fluid level is fine, and there are no weird noises, but it really fights me, especially when turning the wheel to the right. I'll do some searching any maybe start a new thread for that.

Mike

 

[rmcknight]

Carbon is normal in there, it must come from the EGR pipe.
Thats what your cleaning off the butterfly.
The best way to clean the TB is with the car going, and spray in and around the TB, the car will almost stall, but that also helps clean the tops of the pistons.

 

[D Hook]

I wasn't aware you could run the engine without the air tube connected from the air box.