mayraliz76

Hey! I've been having several issues and have been going by what's on these forum to guide me. I don't do mechanic and don't know much but after reading these forums then going to a mechanic they look at me like I know what I'm talking about so first of all thanks to all your posts they do help!

Now, my service engine light came on. I went to Autozone & Oreillys and both gave me codes P0171 & P0174. Guys at shops recommended I use a fuel injector cleaner then run it 100 miles. So I did light still on. I also did the following before taking it to get the engine light problem looked at: 1.)tune up which I needed. 2.)Changed my oil. 3.) Checked for leaking or cracked valves.

***Other problems I noticed when the service engine light came on was that my RPM needle jumps up and down (even more when I turn the heater on, there's also a whistle noise off & on coming from my front passenger side, and truck acts as if I'm running out of gas (once in a while).

Now I took it to a mechanic and he did the diagnostic w/the "accurate" machine that's woth $3000 . Anyhow he got reading P0401 then told me it was my oxygen censors. Sooo he changed them. Truck feels smoother. But my RPM needle still jumps not as bad but it still jumps. Then when I turned into my street from leaving the shop my service engine light turns on again!!!

I got on this website and now it seems it could be a leaking valve like I assumed all along, ICV valve OR my EGR!!! Dam I'm really stressed over this. Can someone PLEASE help me!!!

mayraliz76

By the way the truck is an 2001 f150 lariat 5.4.

Becca

You might get more responses in the General F150 section, not the Member BUILD section.

I'll move it to the correct section.

mayraliz76

Thx! I'm new as a member and I'm still trying to get the hang of it.

mayraliz76

So it turns out my problem was the idle control. It has a huge leak! Replaced part for $60 but labor was $140! Dam I wish I was a mechanic!

mayraliz76

Ok so when I picked up from mechanic he said it was not the idle control. He said it looks like it was a gasket that was torn up. So told me to take home and ride around. If engine light comes back on to go back to him. So like clock work after the 2nd start up the light came back on. Next day I cleanded the EGR which was very clogged. I was told to clean it by soaking in gasoline over night and it cleaned it. Put it back on next day. But engine light came back on after 2nd start up. So it's been nothing I've assumed. Now I want to know how I can find a valve leak? Any advice anyone please!

redseal97

with unsteady rpm needle and a whistling sound i'ld look for a vaccum leak(intake, plenium, hoses,etc) if you still want to check for leaky valves you'll need a vaccum guage and a chart to tell you what the guage is saying....they use to have them in the haynes manuals long ago not sure now....heres a link for an internet one

http://www.classictruckshop.com/club...ts/vac/uum.htm

redseal97

also take a can wd40 or whatever you feel good with( i use anything thats available....within reason) and spray around all gasket areas/joints and if there is a vacuum leak you'll know it quick.

Bottom Dollah

No you don't, unless you can get by on 30k annually with no benefits......

2000xl_toronto

agree with this post, most likely a vacuum leak causing your idle problems as well as the CEL. Never looked at a 5.4 system before but my older 4.2 had a nightmare of vacuum lines. Take your time and check each one individually, most likely you will finally locate the one that is leaking.