So been lurkin around the forum quite abit here the last month or so and the info here has helped quite a bit but i cant seem to figure out this problem with my truck. i got a 2000 F150 5.4 automatic, its got 348,000km on it or roughly 217,000miles. im currently gettin 1131 and 1151 lean codes and it idles really rough majority of the time when u stop at light or whatever, best way to describe it is almost like its running out of fuel. truck runs otherwise quite well while ur drivin it just not when its idling. ive changed the fuel filter, spark plugs, DPFE sensor and hoses, checked for vacum leaks and cant find any, air sensor seems to work fine soooo im sorta at a loss. one thing i should note is i do have an exhaust leak somewhere its either the donut or the manifold itself on the passanger side cant pinpoint where its leaking from. i really dont think its my 02 sensors cause while they probably need to be changed i dont think they would cause the severe running problems im experiencing could be wrong tho i guess.

anyone got any ideas or sujestions cause im outa ideas with this thing...

 

How long has it been since you changed your o2 sensors? They may very well be the cause of your truck running lean if it been awhile since theyve been changed! (i think youre supposed to replace every 100k miles, but dont quote me on that.) It may be that they just lean the truck out at idle, and not at cruising speeds. Other than that man, have you checked what your fuel pressure is? I'd check it just to rule it out!

 

no i havent check fuel pressure but i really dont belive the problem lies in the fuel system as i would think a fuel system issue would result in poor performance while driving,idiling etc throughout the rpm range not just at an idle and i would think it would be a constant thing not like i get, where every now and then it just seems to majically fix itself and idles perfectly fine and then 2hrs later BAM chuga luggin away again..........

also i dont know for sure but i have a hunch they are the original 02 sensors....... if not they are pretty old, i have never changed them myself and i bought the truck from a construction company that was goin out of buisness and from the condition that alot of other maintenace and wear items where in i seriously doubt they ever changed em either, shoulda seen what the spark plugs looked like lol the diodes looked like a thin piece of wire almost completly disentegraded........

This truck has been great to me, got it for next to nothing havent had to put hardly any money into it, been across the country probably a dozen times, its my workhorse, huntin rig, daily driver, movin van lol u name it does everything and this is the first issues im having with it so i cant complain to much but i really wanna get the ole girl healthy again.