okay...this is wierd....My air filter in the 04 5.4 was really dirty, I replaced it...Check engine light came on and truck began to run a little rougher than normal....I cleaned out the dirt and dust in the feed to the TBI which was dirty as well, did not help...I reinstalled the old filter after cleaning it out with a shop vac and check engine light is off ( after reseting the coumputer...negative batt cable ) Truck runs ok...booth Filters are fram and do have the felt gasket..

* 12 weeks to go and I'm counting down !!!!!

 

Your truck knew how to run on the old filter but you changed the environment with the new filter. The truck would slowly adjust over time with the new filter. Reseting the computer sets the engine back to "Standard" parameters and allows it to learn faster. I think the O2 sensor are engaged later in the driving cycle for fine tuning but I could be wrong.

Oops, maybe I mis-read your post. Did you reset the computer when you put the new filter in?

 

Switch to a motorcraft filter and you won't have any trouble. Other than stopped up filters.

 

Motorcraft is overrated and over priced at Ford dealers...Now this truck stalls out at randam and ildes higher than usaul on start up and gas mileage is non exsistant, no check engine light, I'm going to to flill up the truck with 92 octane and shake it out on the highway, could be bad gas or a flue filter, or a 02 sensor, as you all know I factery orderd a new dodge Ram I hope the F-150 can stay togethier for the next two to three months...

 

Your upper intake is probably crapped up with dirt. Same thing happened to my dads. He used napa air filters and his truck stays in the dirt. You know that putting hi octane gas in it isn't gonna fix it, so that's a moot point. Now, why don't you try cleaning the throttle body and other intake componets and see if it fixes it. Then come back and post what you found. I don't think an O2 sensor will make it stall out, so you can forget that. A fuel filter wouldn't cause a high idle on startup, so you can let that go. Bad gas probably wouldn't cause a high idle on startup..... Shaking it out on the highway probably won't fix your high idle problem.

 

in my first post, I cleaned out the TBI and air intake, I took apart the air intake and cleaned it out, its was extreamly dirty and the filter was gumed up with oil residue and dirt, I wounder if a clogged pcv could be the cause the dried oil gunk in the intake and the stalling out problem...

I did put the 92 octane in the gas tank and I run it dry, truck ran better on the high way but still struggels at idle, even with old or new filter...

 

How about cleaning the MAF?

 

It sounds like you have more than one issue, but I would start by replacing the PCV valve, and making sure there are no air leaks anywhere in the air intake.