I need help with my 2001 Ford F150 XLT SuperCrew, my check engine light came on beginning of march, codes are P0171 & P 0174- My dad & I changed all vacuum lines, Changed the PCV valve and it is still giving me these stupid codes. it also is now starting to act like it is on a carburetor instead of fuel injector. when i turn it over it acts like i need to give it gas, goes real low catches then revs up real high about 30 second later stabilizes. i have replaced my fuel pump twice and each time i had to i was driving and just lost all acceleration but still ran. I replaced my fuel filter 5 months ago, my spark plug and wires about 2 years ago. its driving me bonkers, any suggestions?
Thank You,
Really annoyed.....

 

Check for an intake leak?

 

X2. Likely a leak somewhere. Double checked the hoses all over?
http://troubleshootmyvehicle.com/for...d-p0174-page-1

 

We replaced all vacuum lines, fuel line. i also cleaned my MAF, changed my air filter at the same time it runs smooth, but when i accelerate it sounds like i have an exhaust leak and acts like it don't want to go.( We have checked the muffler and pipe, no holes and it sounds like it is coming from under m hood.) and i'm going thru gas like no other....... How do i check for an intake leak? Thank you all for your help i'm about ready to throw a wrench at :"Sheila" !

 

Clean the injectors? Mine was running lean for months,then all the mud in my gas tank caught up to me and all the injectors have been cleaned several times,all the lines have been flushed and I had to clean out my gas tank. Also had to change my fuel filter 3 times in two weeks.

 

Hey man! I had exactly the same issue as you, then today I decided to go deeper. I found a vacuum leak on the PCV hose on the elbow connected at the other end of PCV. Its a rubber elbow and its a little hard to get there. How did i find it? Because with the engine working it sounds like a whistle overthere. Ask somewhone to listen carefully when you turn off the engine. Its very easy to hear that whistle. Hope you find it!

 

Be sure and make sure all of the plugs are tight. Sometimes an exhaust leak sound can be a plug about to launch.

 

We replaced that hose when we replaced pcv valve itself, it was fine but i just did it to be sure.....

 

I did that yesterday as well, all snug!

 

So i finally took it to a shop and it was my fuel pump going bad, $620 later i am up and running and " Sheila" is purring! i guess this time it gave me a warning before it just died on me!