Ford Expy wont idle

sublauxation

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Funny thing this AM, I got my 04 Expedition cleaned up and ready to sell so it's been sitting more than usual. I last drove it Sunday, just pulled the boat around from the alley to the street. When I started it the RPMs shot up to about 1600 then it dropped down to a smooth idle at 1000 and ran fine.

This AM I went out to move it and it fired right up, sat at 1000 RPMs for 1 second, dropped to about 400RPMs, chugged for a second and then died. I tried starting it about 5 times and that's all that happens.

I know I have a small power booster leak and am wondering if that could be the problem, maybe it suddenly became a big leak? I'll replace that tonight or tomorrow and see what happens. In the meantime I was wondering if you guys have any other ideas or have had this happen. I know these Expy's, like most vehicles, all seem to fail at the same places for everybody.

Thanks for all and any info!
 

Volphin

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I've seen vacuum leaks behind the TB, and next to the IAC cause all sorts of havoc. These engines are not very tolerant of vacuum leaks. YMMV
 

Harritwo

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I have seen the Mass Air Flow Sensor cause the surge in idle and poor start/no start condition of the Fords. Check and Clean it, Can of MASS AIR CLEANER is fairly cheap at Oreillys, Autozone. Dont use anything else though.
 

MTboatguy

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First of all what motor does it have in it, the V6 or the V8, if it is the V6, they are junk for the most part, I have an 03 sitting in the driveway right now, that I have to pull the engine and replace the timing chains on and yes it is chains, not chain, those timing cassettes can cause all kinds of trouble when they break, I have replaced the motor once in this thing and now have to pull it back out and fix the chains on it again. Second, the Mass air flow sensor needs to be tested, they go out quite frequently and cause all kinds of problems as well, I have replaced a few of those as well.

I love the car when it runs, but I have had to do thing over and over again so many times, that when I get it fixed this time, I am selling it and buying something else.!
 

sublauxation

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well, the brakes work great now, and it will idle for 30 seconds, but that's it. A friend who is a mechanic did the plugs a couple months ago and there was 1 vacuum line I pointed out to him that went nowhere. He said it doesn't attach to anything. I was suspicious but the truck ran great. Could that be it? It's over the steering knuckle but I can't see anywhere that it goes.
 

sublauxation

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4.6. I took off the IAC and cleaned it up but it looked just fine, also went over the MAF sensor again. I 2 footed it to a shop a couple blocks away and they got 2 codes, both non specific for lean condition on cylinder bank, 2195 and 2197. Sounds like vacuum leak is the most likely cause, I'll take everything apart again tomorrow and look again. There are a couple Youtube videos which gave some ideas. The PCV hose isn't cracked but it's pretty loose so I'll look into that again. Those hoses are not cheap! The mechanic at the shop recommended shooting a can of carb cleaner around and listening for the idle to kick up but it's hard to keep it idling in the first place. He also mentioned that the intakes on these like to warp in back and I don't like the sound of that at all! I'm only at 99K miles but then again......
 

sublauxation

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I looked at my new to me Expedition and it looks like that vacuum line with no home goes to the break power booster on models with traction control or the electric assist booster which mine doesn't have, so it's not the problem. I couldn't feel any vacuum on it anyways.
 

sublauxation

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I found a badly kinked vacuum line running from the back of the throttle body to the passenger side valve cover. I replaced it and thought all would be well, but no luck. And this was the weekend I was supposed to dedicate to getting back into my boat rebuild.:mad:
 

rbh

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Although not the 4.6, my wifes ranger with the 4.0 had a vacuum issue.
At the rear of the engine there was a multi nipple manifold for vacuum lines, a one point the vehicle back fired and popped off a couple of the rubber caps making it run lousy---Replaced the rubber caps and problem solved.
And look for wear patches on the vacuum lines, they could be leaking where they are rubbing.(or cracks)
 

sublauxation

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Thanks for the info, I'll keep looking. I now oficially hate vacuum lines! I shot an entire can of throttle body cleaner around everything while it idled and couldn't find anything. I replaced the fuel filter becuase it was cheap and easy and still no difference. With it loping along I unplugged the IAC and it died immediately, so there's a good chance that's working.
 

hungupthespikes

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Next time is stalls do not turn it off, restart from the on key position.

I always just kicked it in neutral and turned the key to start. The motor would race then settle in to a little higher idle, then over time lower the RPMs again.

Ford continues to lean out the fuel so you get better MPG. It becomes a problem as the miles get up there. It will raise it's ugly head now and again and will give you the same problems you are seeing and the codes too.

The computer will reset the idle only if you do not turnoff the key.
Most likely it's a leak, but you'll never know until you reset the idle.

huts
retired FMoC
With 4 kids in 5 years and always buying Fords, we ran thru a lot of cars/trucks, trust me, it happens with them all, and around the 100k mark.
 

sublauxation

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Well, I bought a couple ft of 3/8 vacuum line, a plastic in-line splice, and a pack of Swisher Sweats. I blew the smoke in throught the brake booster line with a rubber glove over the throttle body and my kid holding his thumbs over a couple vacuum lines we couldn't otherwise plug. After a couple minutes smoke started rolling out from under the EGR valve. We'll know more tomorrow!
 

sublauxation

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I realize I'm now hogging this forum with my Expedition but it still isn't running.

This AM I took it to a shop. They couldn't find any more vacuum leaks so they put in on the big computer. Supposedly it needs both O2 sensors in front of the Cat replaced. The codes coming up show them both stuck lean and according to the "big computer" the outputs form them aren't changing. They also said it needs a new PCV valve.

The PCV valve was rattling like crazy last time it idled so I thought maybe it was sticking open at idle when it should be closed. They wanted $50 to do that so I bought one for $12 and replaced it in their parking lot in about 2 minutes. Maybe that wasn't the classiest move but the owner had no problem with just doing the diagnostics and letting me fix the pieces. Regardless, it purred like a kitten for 20 seconds then dropped off again.

The O2 sensors are about $50 each and not to bad to get out but it seems like a weak diagnosis to me and I feel like they're going to send me down a path of replacing pieces 1 at a time.
 

Boomyal

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I realize I'm now hogging this forum with my Expedition but it still isn't running..

Don't worry about that sl, there is nothing else going on here anyway! btw, what does your name refer to? It is close in spelling to 'subluxation'.

How many miles on that 'splorer? Seems odd that you would have two failed pre-cat O2 sensors at the same time but they are pretty straight forward to test.
 
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sublauxation

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99K miles on her.

I talked with the mechanic today and it just makes it murky....could just be a misunderstanding?

The scanner gives 2 codes: Lean condition bank 1 and Lean condition bank 2

The mechanic says the O2 sensors are causing those codes.

The big computer graphing what's happening shows the O2 sensors stuck reading high voltage, meaning running rich.
This makes sense as it would then dump in less gas, causing a true lean condition.

But then the O2 sensors should be causing a code saying that it's running rich (though in reality it's truly running lean), because that's what they're actually passing on to the PCM by being stuck at high voltage.

That or I'm misunderstanding what the codes mean, and the PCM kicked out a code saying it's trying to make it more lean but can't. That would make some sense but then the code should say "trying to cause a lean condition".:confused:

So either I'm misunderstanding it all, the wording is backwards of logic? Regardless, it's taking away from time I'm supposed to be working on my boat and it looks like she wont hit the water at all this year, and that's the same of it all!

As to Sublauxation, my last name is Laux and I'm a chiropractor. I'd love to take the credit but my wife figured out that Laux fit into Subluxation quite nicely.

How about Boomyal?

.....and where did everybody go? I realize the upgrade was an issue but I'd have thought they'd all come back.
 

sublauxation

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And yeah, 2 bad sensors at once? I have the bad luck of the Irish but that's odd and I'm suspicious.
 

Fleetwin

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EGO's and HEGO's can and do wear out. Also a slug of some high alcohol fuel can play havoc with them.

If your front Cat is bad (clogged or broken internally) the engine can't breathe consistently so the PCM is constantly hunting for the right fuel/air trim. Cause and effect, the EGO/HEGO situation probably took the Cat. out.

By the way, this is an Expedition, not Explorer-correct? The 4.6 in the Expy. and the Explorer are two different animals.
 
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sublauxation

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Yeah it's an expedition. According to the scanner the sensors are both stuck at high voltage causing a lean condition. That makes sense to me but the code it's showing doesn't.
 
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