I just bought this truck yesterday here is what it is doing.
01 Expedition 5.4 110k miles

no CEL on.

if I keep a very steady light foot on the pedal on flat road I can maintain speed but if I try to accelerate normally (w/out babying it) it will misfire/shutter
If I step on it while drive it will act like the truck shut off and slow down, sometimes I see the rpm's jump up a bit while stepping on it but runs like crap and shutters.

So today I took out 2 spark plus and cop's and the 1st cop is brand new(passenger side closest to front end) the coil looked good but someone put in a Bosch platinum and didnt look to good, then I took out the one right next to it (2nd one back passenger side) and the boot had rust on it and so did the plug but it was a motorcraft.

I changed both plugs in the process with motorcraft and changed the one rusted boot.

I also cleaned the MAF but after doing those things didnt make much of a difference.

Also it doesnt seem to make a difference if its cold or warmed up.

I'm hoping the one cop boot/plug I saw that had rust on it was not cause an intake leak/crack and hopefully from someone just washing down the truck.

I know I should probably change all cop's and I will when I get some extra money.

but based on the symptoms of how it drives, flooring it>>losing total power would ring a bell to someone.

thanks

 

You are most likely on the right track. The difficulty for you will be finding out which cylinders are misfiring under a load; difficult if there is no CEL on. Maybe you could try to get a CEL by putting the truck under a load in such a way that it throws a light, like running it as hard as you can up an incline? If that happens take it right to an Autozone or whatever auto parts place will read your codes WITHOUT shutting the engine down! If you can't do that, check all COP's and change the plugs for starters. Remember, just because the oP looks good doesn't mean it is good. Good luck!

 

You need a code reader that can show pending codes.

 

I have driven it over 40 miles and still no cel on as the previous owner shut it off and did not record the codes. I do have a matco code scanner but waiting for cel to come back on, i did notice that one of the spark plugs i pulled out was not tight so i dint want to be driving it to force a code by pushing it just in case another one is lose and i push a plug out the head

 

Since you just bought this truck and will presumably be keeping it for a while, I'd go with a new set of plugs and COPs. You can get a set of 8 COPs off eBay for $70 shipped instead of paying $70 each at the auto parts store.

 

Not sure if they are china copies but I just bought a set of 8 motorcraft oem cop's and 8 motorcraft plat plugs (all one auction) for $94.00 ...so we will see if they are junk copies or the actual ones....

yes u read that right, 8 motorcraft cop's and 8 motorcraft plat plugs for $94.00

 

has anyone here experienced the job of plastic intake manifold gaskets and how hard/long it took them 1st time around? Just wondering just in case it ends up being the problem since i did see rust on one of the coil pack boots...

 

Can't hurt to check the rubber elbow at the back of the intake. You might just be dealing with a large vacuum leak. It's a free check and will only take a minute or two.....you might get lucky.

Other than that I would suggest getting ahold of a scanner which can read pending codes as mentioned above. Mabey swing by a local Autozone or equilivant.....they normally will check it for free.

 

ok well so far I have changed all 8 cop's, motorcraft plugs, one fuel injector and the fuel filter...the fuel filter was dirty and looked like some sand in it...not sure tho... I thought it was fixed but as I took it down the road it started to lose power again and had a little bit of a shutter to it....
I can play with the gas pedal at steady to run ok but not 100%, and again as I mentioned before I have a matco mini scanner and it showed me the codes of cop #2, but since I replaced all of them including injector on #2 I erased the pre-existing codes. I shut the truck off after my little spin and left it alone for now.... I'm almost thinking it might be the fuel pump. Is there a way to check to see if it's the fuel pump by a fuel pressure gauge?

I'm at a loss now and I paid a guy to do the above work cause I am too busy with being a single father... just put $400. into it including parts and Im at the point of just trying to get it fixed and get rid of it...

uhg!!!!

 

That's pretty much the only way to check it.

 

X2 check your fuel pressure on the rail, key on first, then start = in the low thirties, unplug red line to fuel reg, should jump to high thirties,forty, reving engine should raise pressure towards forty

If red vacuum line is wet with gas when you unplug it =bad regulator

Intake gaskets around 4 hrs to 6 for the unexp.alot of belly time on the rad. use oem gaskets only , passenger side is thicker for a reason, torque in proper sequence and proper torque hope this helps

 

when I had a bad CEL, it took 3hrs of driving on my road trip before it threw a code.
It might be a good idea to go ahead and replace all plugs and COPS if you can afford it.

 

as I stated above I already replaced all the cop's and plugs.

Im thinking maybe fuel pump or gunk or whatever in the gas tank cause the guy who did the work said the old filter was very dirty and possibly sand/dirt coming out of the filter.
Tomorrow I am going to rent a fuel pressure gauge and check the pressure.
This guy who is working on the vehicle I heard was a very good mechanic (back yard retired mechanic) but I had to supply a obdII scanner, he doesn't have a fuel pressure gauge and has more less been doing process of elimination (having me pick up parts that I possibly didnt even need)

So hopefully its the Fuel pressure regulator cause I dont want to know what he will charge me to pull the tank to do whatever with the fuel pump...

 

ah, sorry. I didnt read about changing COPs/plugs.
I read the first few posts then replied.

Have you looked into the possibility of a vacuum leak?
I hope it's a easy/cheap fix...let us know about the FP.