Hello,
I'm new to these forums, but let me get started right away. I have a 2001 Expedition 2WD with a 5.4L. About a year ago it started this hesitating thing. If you watch the RPM's at idle it will go from about 700 to 450 back to 700. Even not when in gear. Also, if you are accelerating like normal, it will hesitate and then go a little, then hesitate again. I had looked online some, and it looked like it was going to be a bad Coil Over Plug (COP). I had AutoZone check the codes, and they said that it was a cylinder #1 misfire. So I swapped cylinder #1 & #2's COPs. Then it took it about 3 days to act up again, and another day or so for the check engine light to come back on. Had them check the codes, and again they said it was cylinder #1. So I knew that the COP was fine. So I was going to replace the spark plug or the fuel injector, but I waited till it acted up again and the check engine light came back on. I took it to Ford, They game me a long list of different cylinder misfires. I was like WHAT???! Anyway, they wanted to replace all of the COP's and the Spark Plugs. I said forget the COP's, but replace the Spark Plugs. They replaced one COP boot on Cylinder #6 because they said it had a crack, and they replaced all of the plugs. I got the Expedition back from them, and what do you know, the same thing!!!! So, I had auto Zone check the codes again once It threw the Check Engine light. What do you know, cylinder #1!!! So I thought that it must be the fuel injector. I purchased a replacement, and put it on myself. But that still didn't help!!!! ARGH!!! Everything has been replaced that goes to cylinder #1 but I'm still getting a cylinder #1 misfire! I think it has to be either the wires that go to the COP, or the wires that go to the fuel injector. Can anyone help me with this, or tell me where I can go to get the wires tested?
Thanks!
Dathan

 

I am having the same exact issues. Mine gets worse when it is humid or wet out. I have changed all of the coil packs also. I changed the right side one night and stopped because it was getting dark. That night it ran great after the right side was done. The next morning when I did the left side, it ran like crap again right away. I am going insane with it. I have since had a scanner tell me it was # 7 again. There is an issue with the line from the A/C dripping condensation on the back passengers side pack and it burns it out. But my problem is some times #7, then # 3, then any other one under the hood. Once in a while it will all of a sudden run great and the check engine light goes off, then out of the blue it goes back on again and runs like a pile of junk.

 

Well, funny thing is, mine won't act any different if it's 103 degrees outside or 30, or raining or sun shining. I don't wash it that often. And the codes have always said it's Cylinder #1, which is up front. I believe I have a wiring short, or a connector problem. Once when the engine was running rough, I jiggled the wires going to Cylinder #1's COP & Fuel Injector, the engine instantly stopped shaking! I thought, oh that must be it! But since then, I've jiggled and jiggled, but it won't stop the engine from doing its thing.

 

Maybe the connection is completely broken now. Seems like somewhat of an easy fix.

 

I put new battery cables on now, other cables had corroded ends. Still, of course, nothing. This time, I pulled the COP electric connector plug off entirely, and the engine ran bad just like it was running with it on. This tells me that the wires are definitely bad to the COP connector because the COP itself is brand new.

Anyone know where I can get a wiring diagram?

Thanks again PPLz

 

I had similar problems a few years ago on my 98. Have you checked for a vacuum leak?
I'm not sure of the name, but I had a leak at the very back of my engine (up top) where the vacuum line goes in. I could feel it with my finger and it changed the engine idle if I covered up the hole. Sorry, I'm not a mechanic, just a suggestion.

 

Don't know if this will help or not, but about 2 weeks ago I finally had mine scanned at advanced auto and it came up code p1405 which is the upstream hose off the exhaust manifold up to the dpfe valve. code p1406 is the downstream hose which i did not have that code but I replaced both hoses while I was in there because they were both brittle and literally fell apart in my hands when I touched them. Anyway, replaced both, unhooked battery to reset code and 2 weeks later light is still off and I can't believe how much better it idles, not near as rough. This sight is great.

 

Mine had all of the same problems with showing multiple mis-fire codes when it was actually just one COP that was going bad. It was apparently returning a bad voltage that would shut the enging down to four cylinders. I would turn the key off and it would restart on 7 1/2 every time. It would then show 4 misfire codes. A couple of times it completely died and same thing as above.

I changed out the COP's and haven't had a prpoblem since--about 6 months or so. I bought a full set on Ebay for just over $100.

 

how do you get the cop out?
my cop will move around, but didn't want to pull out. since I haven't done this before, I didn't want to force it. do you have to pry a little to get the boot out?
thanks, G

 

Boots are cheap get one before you pull the old one out as they rip easy.