F150 shuts off and can't figure out why
 

I have a 2001 f150 5.4 V8 with roughly 180,000 miles. Spark plugs have been changed as well. Recently it's started shutting off only in idle. We had Advanced auto check the alternator and the battery, both of which tested good. If we have the lights on and it shuts off, the lights stay on. We've also just replaced the fuel filter and that didn't solve the problem. It only shuts off in idle. Do you have any suggestions?

Clean or replace the IAC.


https://cimg5.ibsrv.net/gimg/www.f15...6c5ac5af44.jpg

Idle air controller. It's on top of the throttle body, remove it and spray WD-40 or similar into it and work the plunger with a small screwdriver. You may need a new gasket if you damage it when removing it.

Okay. I'll try it. Thank you!

I am having a similar problem. It has only happened to me on cold days though.

My post is still active and still trying to figure out what is going on here.

Have a read through this for some ideas.

https://www.f150online.com/forums/v8...af-sensor.html

If I get it figured out i'll let you know!

@Smithtopher


Have you follow the excellent advice @glc and @projectSHO89 gave you in that thread? The key word seems to be "similar". The OP of this thread seems to have different symptoms, and has not mentioned a too lean code.

@F150Torqued

I am following that advice, when I get the time. Unfortunately I am a very busy person so I am doing my best to get this taken care of. Also, horsyluvr did not provide any error codes so I was going by what I have experienced. I am also shutting off in idle so surely it would make sense to reach out to horsyluvr to see if we can figure something out.

Ok.

check vacuum leaks as they will cause the truck to die at idle sometimes

Weve replaced the IAC. The old one had no spring in it. However it didn't solve the problem. It just now idles higher. The only error codes it's given are a leaking vaccum hose and spark plugs misfiring. The spark plugs were just replaced in August so we are betting it's the coils. Also we asked advanced auto for their opinion. They said the fuel oil pressure regulator might be bad and to clean it. If that makes a difference then replace it.

We are working on replacing the vaccum hose within the next few
Days :)

I'm sorry I didn't reply sooner. Mine was is only happening on cold days too (around 50 degrees or so.)

My boyfriend talked to some of his friends that work at a Ford plant about this. They agree I have a really bad vaccum leak. So I've ordered a new vaccum hose and it'll be here in a few days.

Which vacuum hose? How do you know it's bad? Any OBD2 trouble codes?

when i had an 2001 i had similar issue, seem like the throttle body, iac and the elbow after the throttle body (and lines off it) needed to be cleaned

I don't know specifically which hose or the codes. Here's the hose I'm replacing it with. I have one that is extremely dry rotted which we are thinking is the problem.
https://cimg9.ibsrv.net/gimg/www.f15...74b203f67c.png