OT...2003 Ford Expedition

Sorry for the OT post but this board seems to have quite a mechanical braintrust. I have a 2003 Expedition with a 5.4 Triton engine. For the last two weeks it stumbles when accelerating mainly between 30-65 MPH. Once it reaches speed it's smooth. Idles like a new one. Put Lucas injector cleaner, replaced fuel filter, cleaned MAF and throttle body. System is not throwing any codes. No I haven't changed plugs because this is one of those problematic plug blowing models and I've been putting that off as it idles well and still gets 16 MPG. As bad as it stumbles I thought it would have some codes....

Any ideas Ford men?

Damn fords, probably no Check engine light either.

Had one last week similar symptoms, Sparkplugs and boots took care of it. The plugs are a real pain, but follow Ford's procedure and usually all goes well.

Joe

Trade it in BEFORE it spits a spark plug.

I've got a 98 exp and a 2000 f150 both with the 5.4. Sounds like a boot on a coil pack. About $4 at oreillys. It should throw a code for a cylinder thought. If it missed all the time, even at idle, then look at a coil pack for over $50. Still would get a code.

Mine was stumbling this winter and throwing codes for both banks being lean. Used gas line antifreeze for a while. New fuel filter fixed that. It didnt' always throw the code for a while. I checked it and cleared it a few times just to make sure nothing else was throwing a code before putting on the fuel filter.

You need that fuel line slide in tool and even then sometimes the lines just don't want to release without fighting with it. It's inside the driver's side frame rail.

Both mine are due for plugs even though they don't really wear out that much. The Exp has most of the engine under the firewall so I'm stretching and thinning my fingers to get in there.

Gonna park both side by side and have a plug changing party some weekend. Let them sit overnight and be stone cold when you pull the plugs. I've heard of dealers pulling the fuel rails and coil packs, blowing out the holes with an air compressor to get rid of crud, and filling the hole up with penetrating oil and leave it overnight. Then loosen a plug a hair and retighten it. Work them back and forth gradually screwing it out more until it turns out easy. Any boots with miscoloration or stretch marks will be replaced but may replace them all.

A bad fuel pump or wire problem may not throw a code but I'm don't think that is your problem. Mine stumbled and didn't always throw codes but you already changed the filter.

My daughter is driving the exp and it was stumbling some of the time but it was showing a code for the #2 cylinder. I took a screwdriver a couple weeks ago and wiggled the coil pack around and it quit missing.

Mine had had three bad COP's and one bad injector. The COP failures would throw DTC's.

It had a slight stumble when idling before an injector went bad. The day it went bad I got a letter from Ford indicating that if the vehicle had a bad injector it would be covered even though it was out of the 36mo., 3 year warranty period so I took it in and they replaced it free.

I have a 2003 F150 with the 5.4 in it, did the same thing, and yep it was the plugs that caused it. Take it to a shop to have them replaced, where they have the proper tool to do it, that is the main reason that the plugs blow out is because people try to change them without the proper tool.

I would have thought with a plug or COP it would throw a code. Strange times we live in when we must take a vehicle to a specialist to change plugs...