I have a 2007 f150 with a 5.4. I am having an issue with a stumble under load. Idle is good, but if you torque it up in drive with brakes on it pops and stumbles. I have no engine light during this.

Weird thing is, if I go about 70 km/h and give it about 1/4 throttle, it misses and shudders violently. If I do this long enough the engine light will come on, and flashes. But by the time I pull over to plug in my code reader, engine light is gone

Any help would be fantastic.

I should also point out that in the summer (it's winter here now) if working the engine hard, it has that awesome issue where the engine rattles, shakes, and knocks at idle

 

Through my experience's, sounds like you have a bad coil. My truck did the same thing. The code showed a misfire on cylinder#3. Switched out the bad one for a new one and my problem was gone.

Good luck.