about a month ago i went to go pull an enclosed trailer (one i used to haul all the time) and got a couple miles down the road and truck automatically started running like crap, misfiring and stuff so i go back 2 the house and get a diff vehicle for the day. end up changing plugs, wires and it does nothing. change coil pack and truck is good for a couple weeks then starts misfiring again. then 2 cyclinders are misfiring and have that lean code p0174 i believe. and then over the weekend i was driving home and at about 65 in 5th gear and bam start losing power so shift to fourth and doesnt have enough power for that gear either so i drive all the way home in 3rd at about 45 mph. it seems to misfiring under loads for some reason.. im guessing that may be a sensor?? also exhaust smells like gas pretty bad too.. my uncles going to come help me tomorow and figure out whats wrong with it. any advice guys??? thanks!

 

same prob here...on my 02 4.2..been doing it for about 4 months but i never drive the truck...my dad does ..he says he dont notice it but hes old..the other day the fuel pump relay went out 2cd time in a year...i am planning on fuel filter and fuel pump and cleaning the tank out...my father is a supervisor at a coal mine and gets company gas so theres no telling what kind of junk is in his tank......have you changed your filter or anything

 

What brand of plugs, wires, and coil did you put in? When you get lean codes, you need to check for vacuum leaks, including the PCV elbow behind the intake manifold. When you smell fuel in the exhaust, you need to suspect stuck fuel injectors. However, it may all be happening due to a serious ignition issue.

Another possibility is clogged cats - a muffler shop can test for that with an infrared sensor.

 

Mine started misfiring / losing power on the highway the next day after working out at a ranch. Not sure whats wrong with it The out a code for an O2 senor but thats it so far.

It was running fine until then. except for the fan belt that i think needs to be switiched out. Getting that done and the two idle and tension pulleys switched out as well as the O2 sensors. That will fix one problem

 

i used motorcraft plugs, cant remmber which wires and a duralast coil i figured out after i got the coil that i should have gotten a motorcraft one but i checked the coil and their all sparking so i dont kno...im changing the fuel filter today and gonna run some fuel injector cleaner throught it ....

 

Did you use dielectric grease in the boots at both ends of the wires?

 

yea the wires came with a lil in them but i put a lil more on them as well

 

Sounds like you have a vacuum leak. Ever check the PCV valve?

Also, check the o2 sensors... one of them failing can cause that code too and make the truck run excessivly rich.