OK everybody, need some advice. My '07 F150 5.4 has slowly developed what feels like a miss. I've searched, but can't find anybody that seems to have the same symptoms as me......some, but not all.

For the last 10,000 miles or so (I only have 47,000 miles on it), what feels like a miss, skip, whatever occur during steady cruise ONLY. It idles absolutely smooth, accelerates fine with no miss, starts perfectly, basically runs great EXCEPT when cruising on the Interstate or when just driving along at a steady speed. Then you can feel a definite, but very random "hiccup".

It almost feels like the old days when automatic transmissions would get "confused" and "hunt" for converter lock-up.

Here's what I do/have noticed.....

1) I have used only "good" gas.
2) RPMS on the tach don't indicate any "burp" when it does it.
3) It's NEVER thrown a code.
4) Once every day or two, I can hear a very quick, muted back-fire (usually
only one).
5) It's more noticable when Cruise is engaged.
6) It's been doing it infrequently for a few months, but has been so infrequent that I didn't even think about it. Now it's enough to be irritating.

I've got Ford's extended warranty (5 years/100,000 miles) but honestly, I'm freakin' scared to take it in with all the horror stories about plugs, even though it might NOT be the plugs (47,000 miles?)

Anybody else had a similar problem, and could it be a coil pack, some sensor, injector, zombie possession?

Like I said, it's never thrown a code, and the overall drivability is good, but that "hmmmmm-BURP-hummmm" is getting old.

Any ideas?

 

How long since fuel filter was changed?

 

I doubt it is the plugs, but there is little reason to fear a plug change. Investigate your dealer's experience and if they have done very many and follow the TSB, they will have a high success rate. If they break one, it's no longer a disaster as they should have the removal tool.

 

My first thought was fuel filter as well.

 

Nope. Have never even considered the fuel filter. Is this an issue that others have experienced? I'll be more than happy to change it out if it could cause symptoms like I'm experiencing.

That's what puzzles me......dead-smooth idle, no codes, nothing except that darned "miss" at-speed.

 

Dude the fuel filter is a maintenence item replace it. your due. I replace mine every winter but I like my stuff to last and work good. You should do at least every 30-40k. With a clogged filter your pump has to work much harded and it wears it out. If you keep the filter clean the pump just might last the life of the truck.
All that said it sounds like a low grade missfire. Could be from injectors not working due to low pressure or it could be a flaw in your coils.

 

Change the fuel filter.....

 

Yea, -That's exactly when your EGR valve opens and the only time it does(@ cruising speeds). Might be hanging and yes that would cause a hiccup/mis , -most definitly.

You should get an insufficient flow DTC, - Doesn't mean your going to tho. Depending on the senor or malfunction, the PCM may require a 3peat before generating CEL and DTC. Meaning,-the component must fail or detect/report a problem 3 times consistently. Intermittent problems may pro-long until the part/problem worsens.

So, yea -Fuel Filter first tho , specially if it's been awhile. Actually the first part of diagnostics here is to rule out the fuel system. I would do that real quick , then "suck test" the EGR valve operation. Those are pretty simple tests. Type "Suck Test" in the "engine" forum search bar for direction.

Good Luck.