Slight miss

So i have a 2011 expedition about 125k miles on it. Had it for a little over a year. Love the truck. Ive put about 25k miles on it. It developed a slight miss or tiny stumble on a 2k mile road trip about 8 months ago thats never gone away.

I have a slight miss at cruise at almost any speed and the engine is not fluid through the rpm range if i get in it. The miss is barely noticeable most of the time but when i lean on the throttle before and after the first shift its a little more noticeable.

Sometimes the idle is a bit rough, i thought that was pretty normal though for the 5.4.

No check engine light, very few misfires here and there on random cylinders with my torque pro scanner. Nothing on forscan.

I have done the following maintenance / repairs (the miss has never improved or gotten worse during any of this)
New OE plugs from ford (no fakes lol)
MSD street fighter coils
Changed all fluids (engine oil, power steering, transmission, rear axle, coolant and brakes)
Full Timing set with ford parts
M360hv oil pump
New thermostat, radiator cap and water pump
I run penzoil 5w30 ultra
New battery

Any ideas? Not sure where to look next, possibly injectors? I took it to a local shop, they could feel what i was talking about but couldnt find anything wrong.

What is your fuel pressure at the rail when the miss is happening? It may be fine during a static test, but when you're accelerating it may not be flowing enough fuel.

Fitts07 said:

Sometimes the idle is a bit rough, i thought that was pretty normal though for the 5.4.

Click to expand...

Definitely not normal. My idle at 550rpm is as smooth as glass.

The next thing I would look at is fuel delivery - pump, filter, etc.

It could also be a roller follower issue. Were all of those thoroughly checked when the timing job was done? Does it have a loud ticking or tapping noise at idle?

Ill check pressure today while driving and see what happens.

I checked all the followers, nothing loose or jacked up looking. I did the timing job without pulling any. Engine idles super quiet but a little rough sometimes, all i can hear is the injectors.

Fuel pressure as mentioned. This might show a bad pump or screen. Don't think the 2011 has a filter?

"MSD street fighter coils" ?? Unless the problem existed before you installed these Chinese dragon-breath contraptions, I'd ditch them, bite the bullet and install something real OEM. I assume you've had the problem before they came?

The filter is integrated with the pump inside the tank. https://www.fordpartsgiant.com/parts/ford-sender-and-pump-asy_9l1z-9h307-d.html

Also, check the injectors. If you look around you can get a full set of Bosch injectors for a little over $200.

Trainmaster said:

Fuel pressure as mentioned. This might show a bad pump or screen. Don't think the 2011 has a filter?

"MSD street fighter coils" ?? Unless the problem existed before you installed these Chinese dragon-breath contraptions, I'd ditch them, bite the bullet and install something real OEM. I assume you've had the problem before they came?

Click to expand...

Yea no serviceable fuel filter on this one. Its a "lifetime" filter in the tank. Which is more like till the end of the warranty.

Yea the miss was there before.

Fitts07 said:

Yea no serviceable fuel filter on this one. Its a "lifetime" filter in the tank. Which is more like till the end of the warranty.

Yea the miss was there before.

Click to expand...

Fuel pressure, then injectors and their connectors?

Im having trouble finding a fuel pressure tester that will work. My harbor freight one is a pos that just went in the dumpster. The one i rented from autozone leaked really bad.

Anyone have a recommendation?

What made you do the timing set and change the coils? I've used cheap fuel pressures gauges and never had a problem with them. Maybe just lucky.

Go back to when the problem developed. What work did you do when it was last ran right? If it ran well before the timing set was changed, you could have a vacuum leak? Have you cleaned the MAF and throttle body?

This may not be helpful, but remember that by far the most common cause of any misfire is bad plugs, bad coils or bad plug gapping.