So I have a 2000 Ford Expedition Eddie Bauer Edition with the 5.4L Triton engine. Yesterday, the engine started making a knocking noise, which only gets worse when the RPMs increase. It's also been stalling out on me a lot more since the knocking noise started. The engine has over 312,000 miles on it (don't know the exact mileage cause the reader glitches out and only comes on every once in a while) and oil changes are done every 5,000 miles. From the smell of the exhaust, I know it's running rich. I don't know any of the previous work (if any) that has been done on the engine. If anybody needs/wants any more information just ask. This is my only running vehicle and my only means of getting to and from work at the moment. So any and all help is appreciated.

 

welcome to this site,
as to your knock,sadly as you state it gets worse with higher RPM' high mileage , As a retired dealer service manager, i would face to face be telling you DO NOT DRIVE, It's possible that it could be a connecting rod knocking or issues with the timing chain,
posting for our highly skilled BYM's , (Back Yard Mechanics) and our dealer mechanic members , we will ask you to post a video, post it to you tube copy paste the link to a post so we can better help you

 

To be honest, 312,000 miles is a heck of a run. Odds are you’re going to need an engine replacement of some sort whether it be from a salvage yard to get you by or a remanned engine. Solid parts making noise is bad, possible dead cylinders is also bad.

That’s likely what you’re facing. The real decision is acquiring an engine and scheduling time to get that done to minimize your downtime.

 

As you & others mentioned, it is hard to make an accurate diagnosis without hands on.
Out of curiosity, how is the exhaust flow & power output?
Does it feel like it is sluggish?
If this is the case, there is a good chance it has fouled the converters & they are choking the engine off keeping the exhaust from leaving the engine.

I am guessing you must have a CEL active.
What are the codes (active & pending).
If you don't have a code scanner, go "rent" or borrow one from your local parts store.

 

@Johnny Paycheck : Doing an engine swap is possible, and I might already have one, I just have to find out if it's the same exact engine or not.
@G2IC_Wraith : I'll go and plug in the code reader and get the live data it's putting out. It has been a lot more sluggish since it started making the knocking noise. I have no problem getting a rebuild kit and rebuilding the engine, I'm just trying to figure out if the part will come in the rebuild kit or if I have to buy whatever is making the noise separate. Also, the check engine light is not on, which I thought was a little weird.

 

Before you pull the trigger on an engine swap I would try to confirm exactly what the problem is. (for a couple of reasons)
I am sure you don't want it to happen again or you don't want the replacement engine to run the same as the old one.
Hopefully the codes will have some clues.

With the amount of miles you have on the engine, there are some very common problems with this generation truck/engine that usually go undiagnosed & unresolved which leads to further problems.
I was suspecting a converter issue since this is VERY common issue & the engine can "act" the way you described.
Often times previous owners let timing issues, injector issues or misfires go for far too long & just get rid of the truck.
Any of these or just age can lead to a fouled or melted converter that will "choke" the engine off.
If you have ever seen the old movie Beverly Hills Cop - the banana in the tail pipe gag is not far off from what happens when the engine can't breath.

I would start with the codes + a simple temp laser.
At full temp check the temp at the front of the converter, the middle & the back.
I don't remember the numbers I got when mine were melted, but the idea is the temp leaving the converter shouldn't be vastly different.
If it is "holding" all the temp in the body of the converter, it may not be letting the exhaust flow through & you may notice a very weak flow at the tail pipe.
While this is by no means a definitive test, it is cheap & easy which may lead you to getting a shop with more sophisticated scanning tools to confirm that the converters are not activating or allowing flow.

 

as stated you need to do a full and proper diagnoses to start, oil pressure check, compression and leak down tests . how does it run with the cats dropped off? rebuild wise . a crate is the best way, most come with a good warranty , a RB kit will not come with a machined crank or connecting rods as needed,

kit wise most i get come with main,rod,cam bearings, pistons ,rings and gaskets, add machine shop services, which today are costly,, again as one weighs in shop costs with parts . crate motor long block 5.4 today runs about $4.000.00 , as this listing shows https://shop.advanceautoparts.com/p/...rchTerm=engine

rebuilding your self ,your going to be pretty close. a example my local shop gets 150 to boil the block 600 to bore, 150 to cut the crank, another 100 to install the cam bearings 20 a rod to press new pistons, valve jobs range with how much work is needed, my last rb was a 1938 dodge inline 8 ,we had 2.5 k just in machine shop, add to the rebuild costs, YOU MOST replace the rod.main ,head damper ,flex plate bolts, they are stretch bolts and can not be reused.

junk yard motors, are you able to hear it run and see the speedo before it gets pulled? likely that's a no, if not are you willing to pull a bad one back out? that's a lot of labor you won't get paid to do, is a 26 year old truck worth what you will need to put into it to you?