5.4 Triton rough at 1700 rpm

[Colorado Ford]

I have a 2005 EB Expedition..about 125,000 It is running rough when pulling a hill around 1500-1800 rpm. When it kicks down it runs smooth and also smooth at idle. I have also noticed a drop in mileage. I am thinking it may be a vacuum leak. Anyone know where I can find a diagram or other thoughts? Thanks

 

[walnuts4x4]

could also be a low grade miss fire from a COP going bad.... when was last tune up done?

 

[Colorado Ford]

about 15000 miles ago.......not getting a cylinder misfire OBD code at all

 

[CARO'S98EB]

A vacuum leak would make it run worse at idle not when accelerating. Sounds like a ignition miss. 05 also had problems with injectors- even had a recall but I think it was only to 100,000 miles.

 

[masterhacker]

Computer wont pick up miss unless its pretty bad, mine wont anyways ive been having issues with my coils obd wont pick up a miss unless i really get on it

 

[masterhacker]

also to find vaccum leak take carb cleaner and spray a little by the vaccum lines, if idle changes you have a leak. be careful its flamable

 

[Colorado Ford]

Threw me a code today, but pretty generic....P0420....left bank efficiency below threshold...could be the coil packs(which seem pretty common on that side), EGR, O2S, Cat, Vac.....I guess I will start with the coil....any other thoughts?