Engine stumble, long running intermittent problem

[Paul2003]

Since I bought my 2003 Expedition a year ago I have had an intermittent stumble/ misfire but no code. Had it in a few times and they always find something to fix but the problem remains. So far I have had the #4 coil and plug changed, the #8 coil and plug changed, the fuel pump changed, the fuel pressure regulator changed, the 6 remaining coils stress tested and the intake manifold and injectors pressure cleaned.

Since the truck came with a 2 year aftermarket warranty I keep taking it in but I'm tired of it and will try to fix it myself now.

It idles perfect and runs fine when cold. It lasts 5-10 minutes but is not bad enough to stop the engine or make you pull over.

Right now I'm thinking of replacing the 6 remaining coils and am looking for suggestions where else to look.

Thanks

 

[RAWPWR]

has all 8 plus been replaced? my 04 did something simmilar, then finnaly a code came out on a misfire. mine was a faulty coil

 

[Paul2003]

I was told they were new when I bought it but the mechanic at Ford thought only the front 6 were new. The rear two have been changed now. I've order 6 new coils from Rock Auto and they should be here in a week. Fingers crossed.

 

[Paul2003]

Got my new coils from Rock Auto. Note to self, if your in a hurry don't go with the cheapest shipping option. A week and a half seems like forever.

Installed them with only minor difficulty and it seems to run fine. Hopefully it's fixed, intermittent problems are a pain in the butt.

 

[metaldrgn]

That's why it's good to have a backup vehicle

 

[Paul2003]

That's why it's good to have a backup vehicle

Yep. Got an unloved but reliable 98 Taurus.

 

[rock3ralex]

I honestly think the issue is a super slow leaking head gasket. I've been replacing coils for ages and all the signs including busting a radiator, losing coolant, and what not. fixed the had gasket and nothing has happened since