Truck is idleing really rough and sometimes really fast too. Had codes read and they indicated it was running lean and autozone said the o2 sensors needed to be replaced. Not sure they do. Truck is 98 with 78k and has the 5.4. We replaced the PCV valve and the hose going to it because it was cracked but this did not help the problem still doing the same. Is it the o2 sensors or what. We are sick of dealing with this. We cleaned maf also. If there is a vaccum leak we can't find it.

Also when you shut the truck off you hear a weird noise kind of like something is bleeding off. Not really a hiss just a light grone or something. Does it like 15 seconds then stops. Could this be the problem.

Any help is greatly appreciated.

 

treat,

read this: https://www.f150online.com/forums/sh...ht=po171+po174

 

Thanks, well we are moving on to the fuel filter. We have changed everything else. Running lean to me would mean it isn't getting the fuel. The truck has 80k and it is time for the fuel filter to be changed.