I've got 2006 F150 with the 5.4L and 116xxx miles. About 6-7k miles ago when I'd be climbing a hill on the highway I'd feel a light shake, almost like the engine was choking, so I'd punch it and no issue. This continued on and off for a while. Recently when it would do this, the engine light would flash on and off a few times then stay off. It did this again yesterday and now the engine light is illuminated all the time. It seems to choke (to me it's like an old car that has a flat spot in the carb, that's the best way I can describe) at low RPM's 1400-1800. It doesn't do it on the freeway if you're above 2200rpm. You can cruise at 1700rpm down the freeway at 70mpg without issue, but if you go up a hill it will shake. I don't pull a trailer nor do I haul anything. Any ideas?

 

Spark plugs would be what I would point at first. Do you know if they've ever been changed?
But it never hurts to clean your MAF and throttle body with the appropriate cleaners.

 

I agree. Replace the spark plugs if they haven't been replaced within the last 80,000km.

 

Thanks for the info. The spark plugs have never been changed. I heard these are hard to remove. Is that true?

 

Its the plugs. Mine did it, after driving with a misfire for to log the wrench will start blinking.

 

There is a sticky on how to remove the plugs. They can be difficult make sure you have the lisle tool incase you break some of them.

 

My truck was doing the same exact thing a couple months back. I changed all the spark plugs and it fixed the problem.... at least I thought it did.
I could never be at low rpms due to the truck misfiring. Every hill I went up, especially in the freeway in overdrive at around 1600-2000 rpm the truck is shaking like crazy.
I talked to my buddy that's a mechanic and we hooked it up to the code scanner. We got misfire on #7 we change CP over to #6 but couldn't get it to shoot the same code error. We got in the truck and drive it around with the code scanner plugged in trying to get more codes out of it. Nothing.....
At one point I had 300 random misfires on a simple freeway on ramp. We got a code stating fuel management error. He claims its the fuel pump. So I dropped off my truck with him yesterday to get it swapped out. At the same time my timing chain was starting to get louder closing in the guides and it had that diesel sound so i decided to change the cam phasers, sprockets, guides, tensioners, and chain. I also got the transmission filter and new transmission fluid to do a swap out since I haven't done that servicing yet. I'll keep you guys in the loop after its all done.

 

Mine did this, spark plugs were done. Got them changed last week now it runs fine.

 

Damn brother that will be a big *** bill!

 

Tell me about it! I spent about $800 in parts all together. The good thing is my buddy isn't charging me labor, just gonna owe him a favor later you know.