Hi

I am new to this forum, I came across you all looking for answers about my 2000 Ford Expedition EB 5.4L.
The codes have come up 171,174 a little while back. I have tried everything pretty much, like, changing the IAC,the EGR valve + hoses, changed the pcv, checked the elbows all seem to be good. I have checked all vacuum lines I could find, still the sames codes come up.
When I start my truck up in the morning it idles very high, then, when it starts to idle down finally, the erratic idle kicks in, up and down and up and down, like it is going to stall, then it finally catches, idles high once again, and smooths out somewhat.
The only other odd thing is, sometimes, I get a high pitched constant whistling noise right behind the air intake, close to the block on the firewall side(or back of motor). I have tried spraying brake cleaner in the area, but, have not heard a change in idle.
Could this be a cracked intake manifold? Since it is the plastic factory one?

I am really glad I found this forum, finally be able to talk to people who know what they are talking about!

I hope someone can help this is my last stop before spending big dollars at the garage.

Thanks Mel

 

Yes it could be. In fact as I was reading the first paragraph you wrote, an intake gasket leak, or a cracked intake is what went through my head.

 

Thank your for your reply alloro. I guess I have a couple more questions if you wouldn't mind.
I was reading they sell a aluminum intake, where could I find one?
Also, would you know what tools I would need (sizes) of wrenches and sockets to complete changing out the manifold and gaskets?

Thank you for your time!
Mel

 

I don't know about that all aluminum one, but rest assured if one exists it is likely to cost close to $1K.

Here the regular replacement one that comes with all the gaskets for $227.79.
2000 FORD EXPEDITION Intake Manifold

 

Thanks for all your help. It can be allot of things I am getting from this forum. So with the intake, I ordered throttle body gasket,valve cover, and everything we could think of for gaskets that could leak, but not head gaskets.
Any way, thanks again , I am sure we will be around for quite sometime, and if this works, I am gonna become a paid member!


Mel

 

Any updates on this. My Exp does the same thing to a tee! Mine does stabilize and run perfect after 10-15 minutes. I did the same things you did as well... Mine is 00 5.4 w/ 86K on it.
Chris

 

TIP: On many Fords, a P0171 and/or P0174 Lean Code may sometimes appear because of a bad Differential Pressure Sensor (DPFE). This sensor monitors EGR flow, and is located on the engine near the EGR valve. There are two hoses that connect the sensor to the tube that runs from the exhaust manifold to the EGR valve. The sensor misreads EGR flow and the computer increases EGR which has a leaning effect on the fuel mixture. The fix is to replace the DPFE sensor.

 

Melody
Since you have already spent time and money--one more suggestion can't hurt. The sound you are hearing is probably a vacuum leak. That pesky 90deg PCV elbow is at the top rear of the engine at the intake manifold. The age of your truck suggests if that elbow hasn't been replaced it is due! There is fairly high vacuum there. That elbow actually can look good and have a hidden pin hole in it. With the engine off it can actually look good. And then when engine starts it can collapse since it's soft and there can be a pin hole at the back side of it that is not obvious.

With what you have been thru, I would look at this elbow one last time while it's running to be sure it's not collapsing and I would pull it off and look inside of it for deterioration. On my 2000 Navigator this elbow is hidden by a cover. After removing the cover my elbow was partially collapsed and had a pin hole in it that could not be seen and the inside was very deteriorated.

Give it one more shot. Pull it off and examine carefully. Can't hurt.

 

If you find your elbow deteriorated, take a look at my post here for suggestions on replacing it.

https://www.ford-trucks.com/forums/3...asy-fix-2.html