hello everyone!
i have a 1998 f 250 4x4 with the 5.4 that has 114000 miles
a month ago on my way to florida with a quarter tank of gas, the steady check engine light came on. read the manual and did the suggested fixes to no avail.took the truck to my freinds shop and scanned on the snap os myos. codes po171 and po174 came up as being a too lean fuel mixture. i read through the forums back to about 6 mos and didnt really find any topics besides checking the pcv hose and throttle body ond valve for debris and wear. here is the situation, one person tells me to change the o2 sensors, another tells me to flush the fuel system and yet another says the chip is bad. if anyone can point me in the right direction it would be greatly appreciated. to add, i had the 100000 mile service done at the dealership, new plugs and fuel filter and i still get the codes coming back even after they have been cleared and my truck still doesnt seem to have the horsepower it should. i should note that the truck has a 3" body lift with 305s on it. once again, thanks for any help

 

Try cleaning your MAF sensor before you do anything. Since this is free it is a great place to start. I had the same colds on my 4.6L and this did the trick after that I hear the rear O2s are the next step.

 

I had the same codes, cleaned the mass air sensor, changed the fuel filter, pcv... never went away... until I changed the Mass air sensor. After spending much time on research of these codes I found the culprit is many times the sensor.....