4.6L 03 Expedition. Check engine light was on, code read random misfire. Rough idle (at times it is borderline ready to quit at idle), very poor acceleration, and misfires if I attempt to accelerate too quickly. On the highway, it takes roughly a mile to get to 65mph and slows at highway speeds when going up a grade.

I unhooked the battery to reset the light and now I have the same symptoms as before but no light after 10mi of driving.

I changed out all of the coils. I soaked the injectors for 4 days in cleaner (even though this does not really clean inside them by soaking), same symptoms.

Any help would be greatly appreciated.

 

Had a similar issue with my wife’s expedition, turned out to be a vacuum leak from PCV tube to the back of the intake housing. Rubber elbow by the intake housing had cracked and the only way to see the part is by removing the cover. I pushed on the tube and that’s when it just disintegrated.