I know there are many posts on here for missfires, and coil pack issues, i recently purchased a 2000 expedition 5.4, was light up like a christmas tree (all warning lights on) i changed the batter, CEL went off. Engine was running rough, so i figure let me change the plugs as i dont know when the last one was done...changed the plugs, got some power back, still riddign rough when excelerating, BUT still no CEL, car is running rough, not much power especially when trying to accelerate when crusing, car shakes like its "needing" something. Has anyone experienced loss of power (minimal power) lack of acceleration and rough idling without a CEL coming on?

Trying to get the truck ready for the wife and kids before the snow is on the road,

 

You can be running rough with no CEL. I had 1k miles of rough running with no code. I had coil packs and was ready to do the job as I suspected that was the issue. I ran into some time drains in other parts of my world and had to bring it to the dealer because I couldn't afford to not have the car on the road. When they scanned it they had pending codes for multiple misfires. They put in the ebay coils / boots / springs that I had bought and life is good.

 

If the car is running rough the CEL will go on sooner than later.

When the CEL comes back on actually figure out why its on, read the codes, before pulling the battery.

While changing all the spark plugs is a good idea there's no point to changing all the COPs besides burning money. (If you leave the spark plugs in for too long they'll seize up)

Wait for the CEL, figure out which cylinder is misfiring, replace the COP and you should be good to go.

 

so no CEL can still have pending codes? and only the dealer can confirm? i am weary of ebay, anyone recomend a good seller?

 

Thanks Speedy, that was my mistake not making a note of the codes previous to chagning a battery, i figured it would come back asap as i had issues starting and acceleration was next to nothing! now i have driven about 30 miles on the new plugs and no CEL..

 

Yea I just had the same issue, if you have a scanner handy give it a try, sometimes it will log a code without flipping the CEL.

I had a bad spark plug and over a week the CEL would come on then turn off.

 

just had the shop look at it with a scanner, no codes! no lights on or off! truly baffleing. to me,

 

The fact that you changed the plugs could have compromised some of the boots assuming they had never been changed. They are 11 years old and rubber tends to dry out and get brittle. The handling of them could have caused a problem or a crack you didn't see. You can also just buy boots and springs and see how that goes.
There are plenty of people here who have gone the discount route for COPS and report good results. There are also people here who have gone name brand and reported problems. You can get a Motorcraft part for $90 each, or you can get 10 for $90 aftermarket and have 2 spares.

 

where can i get the 10 for $90? i am a bit hesitent on Ebay...i am getting an aftermarket from a parts store in canada (parts source) for $55 each...

 

10 for $90 is on ebay, a number of sellers have similar deals. Regardless of who sells them, they aren't coming from a huge variety of sources. It isn't like the sellers are making them.

 

Great info guys Thanks. I'm having this issue ATM .

 

check engine light just came on...on to the shop to see what it is... it was like christmas for me...never thought a CEL would bring me so much initial joy... i do think it has to do with the coil pack, but fuel injector, connector maybe a clogged filter is adding to the mix of things...

 

Some codes are what are called "2 trip" codes. That is, the fault must occur on two successive "trips" before the CEL will illuminate. So when a "2 trip" code occurs, the PCM stores the code in its "Pending" file. If on the next trip (and there is a specific set of rules that the PCM uses to determine what constitues a next "trip") the fault doesn't occur, the PCM drops the code off the Pending file. But if the fault does occur on the next trip, the PCM moves the code from the Pending file to the "hard' fault file and illumintes the CEL.

(If that fault doesn't re-occur in the next 20 (or 40 trips, depending on MY), the PCM will clear that code and extinguish the CEL.)

No. Anyone with a scan tool that has the ability to display "Pending" codes can confirm.

But not all scan tools can display all codes. Codes lower than P0999 are considered to be "generic" codes and are uniform between manufacturers. But the manufacturers are allowed to store codes above P0999. These are referred to as "manufacturer specific" codes to assist in diagnosing problems. Basic generic scan tools are not programmed to display these codes.

 

pdqford! woah thanks for the reponse its time for me to go to the shop and flex some knowledge and let them know!

 

Any chance this could be exhaust related ? My truck only has all of your symptoms spareticly. Its driving me nuts. No codes. Unles I get the truck up to 5500rpm then engine light flashes. But no stored codes since I can't get to a code reader untill I have time Thanks