Rough idle/shaking

[Devin95]

Bought a 03 expedition 5.4 EB edition a month or so ago, picked it up for $1000 since it needed some work. The guy said it needed head gaskets (which it doesnt. Its runs great down the highway, only issue is that it shakes at idle, in drive, and reverse. I've put intake gaskets, plugs, coils, injector rings, thermostat, new coolant, EGR, DPFE, EGR solenoid, IAC valve, new vacuum lines, fuel filter, fuel damper, fuse #32, cleaned the MAF, and changed the oil. Now I dont have any misfire codes. I keep getting the p0403, 2 evap codes, cylinder head temp out of range, and 2 H02s codes. I clear the codes and I can drive it 300 miles and it runs great, until I shut it off and turn it back on then it runs like shit again. Starting to drive me crazy. Only part I didnt replace was the cylinder head temp sensor. It's starting to drive me crazy. I got terrible memory but when I tested the fuel pressure it was 30psi or so. It had a long crank time before I replaced fuse 32. Any info would be great

 

[TobyU]

If a 0403 code, sounds like egr is sticking open when it runs rough.

A perfectly good running one will feel like 2 cyls are misfiring if you open egr at idle in gear.
There is a vacuum solenoid that controls the egr vacuum. Check the hose routing, maybe something swapped.
When you restart it and it runs rough, pull the line off of egr and it should smooth out. It can also stick physically and the vacuum line even being off wont let it close.
For that stick a longer piece of tubing on the egr and blow on it with your mouth. That usually pops them back closed.

 

[1955moose]

On top of what Toby said, be sure port from EGR valve is clear. Very common on your year and 04 4.6 motors. When it's running apply vacuum from a pump, if idle doesn't stumble, you'll need to remove carbon from port.

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[Devin95]

I pulled the vacuum line from the EGR and still does the same thing. I cant imagine that the EGR and the solenoid would be crap right out of the box. They are right from the ford garage. I have a very nice solus pro scanner and I went to live vehicle mode so I could see everything going while I'm driving it and everything is functioning fine. I am completely stumped. And the girlfriend is getting sick of me working on it and not being able to set rid of the shaking.the only other thing I could think is causing it is maybe the TC? If it is that, I have a brand new one and pulling the trannys isnt that hard to do on these IMO

 

[TobyU]

I pulled the vacuum line from the EGR and still does the same thing. I cant imagine that the EGR and the solenoid would be crap right out of the box. They are right from the ford garage. I have a very nice solus pro scanner and I went to live vehicle mode so I could see everything going while I'm driving it and everything is functioning fine. I am completely stumped. And the girlfriend is getting sick of me working on it and not being able to set rid of the shaking.the only other thing I could think is causing it is maybe the TC? If it is that, I have a brand new one and pulling the trannys isnt that hard to do on these IMO

You can't just pull the line to see if it changes. You have to pull the line and put another piece of tubing on it and suck the egr open.
It has to run rougher when you suck on the hose to let you know I to opening and smooth out when you release vacuum I hose.
Do this simple test before considering harder and expensive potions.
Its possible there is carbon rough spot on earth or port and it opened the first time and stuck and has been open since.
This test will tell you if it's opening and closing.
What are your long term fuel trims?
Should be high if you have an evap or other vacuum leak.

 

[1955moose]

You can have a perfect functional valve, but a clogged port through intake, and it won't run right, especially when warm. That's why Toby and I are saying apply vacuum to the port while running. You may have other problems, but best to eliminate this one. Common on 4.6 motors.

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[jeff kushner]

On both 5.4's that I owned, the vac tube that makes a sharp turn over the rear of the passenger side cyl heads, wear or burns a hole in the bottom of the tube, right at the turn....plug it up and it'll run smooth as glass!

jeff

 

[Devin95]

Sorry it's been awhile since I've came back with an update but I figured out why the vehicle idled like crap, after I cleaned the egr ports and put a new thermostat in it, the girlfriend drove it for awhile and the high temp/low oil came on and it died on her a few times. Had to replace the battery and alternator in it and change the oil on it, light hasnt came back on since then. But anyways the rough idle was due to a bad flex plate, replaced the flex plate just out of curiosity and solved the problem. Now if I could just figure out why the heat isnt the greatest that would be awesome

 

[1955moose]

Well when you think you've heard and seen it all, a flywheel flex plate causing a rough idle? I've seen them make racket like crazy, but a rough idle? Guess it was throwing off the balance of the motor, which was felt as a intake leak. I got to remember this one.

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[Trainmaster]

rough spot on earth or port

I like that a lot.

Bad flex plate? How, why? What would inspire you to check that out and then spend the time and money to change it?