Rough idle

[Snapshot]

Hey guys, I'm chasing yet another annoyance in my Expedition (2000 XLT, 5.4 4x4. The vehicle idles very rough, you can see the vehicle itself shake sometimes, but you most certainly feel it whenever it's idling. The engine will throttle up and down, bouncing anywhere from 400-800 RPM and will continue to due so any time the vehicle is idling and regardless of how warmed up the vehicle is. It's only started it since the colder weather has hit here in Kentucky. I hooked up my scanner and it shown 3 codes; P0300, P0171, and P0174. The last tune up was near 150k (new plugs & cops) and the mileage just hit 175k. As soon as I seen P0171 and P0174, I checked my pcv elbow and it was cracked to hell and back, so I ordered an entire new assembly (hose, pcv, elbow), installed it and no change. I have tried spraying carb cleaner along the vacuum lines there was no change in how the vehicle was change. I've also cleaned the MAF sensor and throttle, so what should I check next? I just changed out that damn heater core and I sure as hell am not going to let this stop me.

 

[snozberries]

I have the same issue. I cleaned the EGR valve and changed the transmission fluid at the same time and it went away. I'm not sure which of those things fixed it but it was smooth as butter after.

Now the vibration is back though. Which makes me believe that cleaning the EGR fixed the problem but now the EGR is either stuck again or broken. I ordered a new EGR valve that should arrive tomorrow. If that fixes the problem I'll let you know. It was only 36 bucks online so thats good!

 

[Bedrck47]

P0171 - System to Lean (Bank 1)

The Adaptive Fuel Strategy continuously monitors fuel delivery hardware. The test fails when the adaptive fuel tables reach a rich calibrated limit.

For lean and rich DTCs:
Fuel system
Excessive fuel pressure.
Leaking/contaminated fuel injectors.
Leaking fuel pressure regulator.
Low fuel pressure or running out of fuel.
Vapor recovery system.
Induction system:
Air leaks after the MAF.
Vacuum Leaks.
PCV system.
Improperly seated engine oil dipstick.
EGR system:
Leaking gasket.
Stuck EGR valve.
Leaking diaphragm or EVR.
Base Engine:
Oil overfill.
Cam timing.
Cylinder compression.
Exhaust leaks before or near the HO2Ss.

P0174 - System to Lean (Bank 2)
See Possible Causes for DTC P0171.

P0300 - Random Misfire

The random misfire DTC indicates multiple cylinders are misfiring or the PCM cannot identify which cylinder is misfiring.

Camshaft position sensor (CMP)
Low fuel: less than 1/8 tank
Stuck open EGR valve

You may want to check the two hoses that go to the DPFE Sensor for any signs of cracks or loose fit Also consider replacing the DPFE Sensor.

Although the exhaust ports thru the throttle body don't clog as bad on the 5.4 as they do on the 4.6 it would be best to pull the throttle body and clean the exhaust port.

 

[Snapshot]

I changed the 2 hoses that go into the dpfe back when I done the last tune up. They are still in good shape. I accidentally destroyed the old ones by bumping into them and they practically turned into dust. I'm going to try cleaning the EGR valve and see if that helps. So fingers crossed.

 

[Bedrck47]

if you have never cleaned the port thru the throttle body I would consider doing that would only require 2 gaskets and some throttle body cleaner being you have over 150k miles on the expy also clean the Idle control valve

http://www.expeditionforum.com/f42/about-egr-pcv-dpff-evap-iat-tps-maf-23583/#post191356

 

[xJohnnyOx]

Just to chime in, mine is doing the same thing. Had the same issue last winter too. If temp is below 32, and after 5 minutes of driving, when at idle, the engine will just start sputtering and the revs go from 200 to 2000 RPM a couple of times then it trys to die. I usually just step on the brake and then rev the engine a bit (1200 rpm) to keep it running smoothly. This will go on until the engine is up to full temperature (about 10 minutes), then runs normal from then on. From my research last year, it seemed the most common issue was a leaky pcv hose. I just picked one from the junk yard and will install when it gets a little warmer and report back. Also, I would check the PCV grommet as the one I changed out last year was so hard and brittle, I would anticipate it was leaking a little too.

I will report back on if the hose change has any effect.

 

[Snapshot]

As I said before, I replaced the entire assembly and there was no change. I've smothered nearly every line with carb cleaner and still haven't found the culprit. I'm finally going to have time today to clean the EGR and IAC valve. I have noticed that it will not do this whenever the vehicle is started. Only once it begins to warm up the slightest it will and even after being fully warmed up. Last year it would do this very rarely when winter hit. It happened whenever I'd stop at the light before I got onto the interstate. It was usually about 1/5 of the way warmed up whenever it did do that, but it stopped whenever the engine got fully warmed up. Since it's not doing it when it's first starts, I'm having my fingers crossed that the EGR is dirty or stuck. I think I read somewhere that it doesn't activate whenever the engine isn't warm (need verification on that).

 

[Bedrck47]

the egr valve operates off of vacuum so what does that have to do with being warm or cold

 

[Bedrck47]

you may want to check the EGR Vacuum Regulator (EVR) Solenoid
see attached

 

[xJohnnyOx]

As I said before, I replaced the entire assembly and there was no change. I've smothered nearly every line with carb cleaner and still haven't found the culprit. I'm finally going to have time today to clean the EGR and IAC valve. I have noticed that it will not do this whenever the vehicle is started. Only once it begins to warm up the slightest it will and even after being fully warmed up. Last year it would do this very rarely when winter hit. It happened whenever I'd stop at the light before I got onto the interstate. It was usually about 1/5 of the way warmed up whenever it did do that, but it stopped whenever the engine got fully warmed up. Since it's not doing it when it's first starts, I'm having my fingers crossed that the EGR is dirty or stuck. I think I read somewhere that it doesn't activate whenever the engine isn't warm (need verification on that).

Sounds like our problems are identical. One other weird item is that when I stop at a light, it will idle great for about 20-30 seconds before acting up. i look forward to any solutions you come up with!

 

[Kermit]

Stupid question but... Broken motor mount?

 

[snozberries]

So I changed the EGR valve and it seemed to do the trick on mine. Hopefully cleaning yours does the same thing. Although, the only reason mine went bad in the first place is because I got throttle body cleaner all over the motor that your not supposed to get cleaner on apparently. (at least I think that's why it went bad).

After I cleaned it the problem went away then all of a sudden it was back. I had started noticing the erg valve making a noise (at east it sounded like it was coming from that region) as soon as I turned of the engine and opened the hood. So I replaced it and problem solved.

Good luck!

 

[98DOHC]

When was last time you changed your 02 sensors this could cause your symptoms.Iac could also cause really rough idle and dieing if plug is not tight.

 

[WacoStang]

Recently had a similar problem, bad idle once it warms up. Put a new IACV on it, now it runs like a top. You could try cleaning it I guess, but I figured at 215K miles it was worth the $50 to put a new one on. As far as vacuum leaks, I've been told by a ford mechanic that the elbow right above the PCV valve is where it goes bad often, either with a hole, or the line gets weak and will actually suck close, so check the first couple of inches of hose there.

 

[rvm1]

Recently had a similar problem, bad idle once it warms up. Put a new IACV on it, now it runs like a top. You could try cleaning it I guess, but I figured at 215K miles it was worth the $50 to put a new one on. As far as vacuum leaks, I've been told by a ford mechanic that the elbow right above the PCV valve is where it goes bad often, either with a hole, or the line gets weak and will actually suck close, so check the first couple of inches of hose there.

Had exactly the same problem. . . which was corrected by the exact same solution