Howdy fellow F150'ers,

This is my first post since joining... and I must say that I'm proud to be here and be a part of this forum.

First off, I have a 2001 F150 w/ 5.4 4x4 extended cab... 156,000miles on her. I just purchased her two weeks ago. I have since replaced the spark plugs and coil packs....which appeared to have NEVER been replaced (just a testament to the good quality of the truck imo as these plugs and coil packs were in extremely horrible shape). I also have put in 2/3 can of seafoam into the engine to clean her out and will be changing the oil in the next day or two.

I am having an issue with a rough idle. I have the following CEL codes:
p0401/p0171/p0174.

From what i've read on here, the lean bank codes typically mean a vacuum leak somewhere along the intake ... which i'm planning on trying to hunt down ASAP. I will also be cleaning out the MAF as well (side note, i took apart the intake/throttle body and cleaned out the carbon build-up as well)

Back to the rough idle, generally speaking this occurs mainly during cold starts in the morning..it'll begin idling at around 1000 rpm and then drop down to around 500rpm and flutter around that area... kinda feels like she's going to die. So, i figure the IAC valve is either clogged or wearing out. I'd like to clean the IAC valve rather than drop $60 on a replacement part if its possible...

Any thoughts / suggestions? Thanks in advance!

 

You can definitely try it, it wont hurt. Get a can of carb cleaner and go at it with a pipe cleaner or other little brush. As for the lean codes, use the same carb cleaner to spray the vacuum lines and around the intake, throttle body and plenum gaskets while the truck is running and if it revs up you've found a leak.

For the p0401 when you had your throttle body off did you pull out the plenum and egr valve and clean the egr ports? That is pretty much the cause of p0401 every time.

 

I didn't take apart the EGR valve ... I didn't even think about it honestly. So, I can pull that apart and clean it out like I did the intake huh? Is there any walk-through on here with pictures or anything that you know of? Thanks for the advice.

 

That's not really what I meant. You have to take the egr valve off and check the ports in the plenum that go fromthe valve to the intake. If you take the egr valve loose you should be able to move it enough to get a long screw driver down in the port and I bet you'll find it plugged up. That egr code isn't related to your lean codes though so you still probably have a vacuum leak or left a line loose somewhere.

 

yeah i knew what you meant after i re-read it haha...

I took the intake off the engine last weekend and cleaned it out with carb cleaner (it was pitch black on the inside) and tried to get what I could out of the holes/ports on the side of the intake...

so I'm wondering if i either didn't clean it good enough or if the EGR is having other issues...

I did drop by and pick up an IAC during my lunch hour as a "just-in-case" if cleaning the original IAC doesn't work...although i'm not really wanting to tear it off the back of the intake more than I have to.

 

Those two small ports you cleaned turn into one bigger one and go all the way to the egr valve. Chances are if you had a lot of junk in the two smaller ones it's also plugged solid where it gets larger. Tell you what you can do is with the truck idling use a red or black, or any other vacuum line that has vacuum on it at idle and put it on the egr valve. When you apply the egr to the intake at idle the truck will try to stall out, if it doesn't, pull the egr valve off and try to stick a little screwdriver in the port behind it. If the egr is working, replace the dpfe sensor, which is the one that has the two silicone hoses going from it to the egr tube.

Cleaning the plugged egr ports kind of sucks, you need a real long pick and a couple cans of carb cleaner and some time. I like CRC gum cutter, that's some strong stuff.

 

Ah, thanks for the info! I bought Gumout Carb Cleaner to take care of that...

a little update: I replaced the IAC valve and found the vacuum leak. She idles just like I expect her to now. I haven't had a chance to get the engine codes cleared, so I'm hoping to do that in the morning and see what the ole computer has to say from there.

 

I know this is an old post but where did you find your air leak? I having almost the same issue. and having a hard time trying to find the issue. But mine it not putting down codes..

 

Sorry I just now saw your reply to this post....

If I remember correctly, It was either the elbow / hose on the back of the IAC or it was the gasket from the IAC itself. Hope that helps.

 

I wouldn't use carb cleaner on the throttle body though. Brake and carb cleaner can eat a protective coating. Here's what I use