I_killdeer2

same problem here, 4.6 replaced battery, can barely drive it. will do the relearn trick in the morning. anyone have any more input on the issue? things that worked?

JCooper

Let PCM go through what's called a "normal drive cycle". It might be described in your manual. Involves a certain amount of highway and city miles with a certain number of stops/ idles in between (like when you stop at a red light). If the problem persists, hopefully it will throw a code.

**** Fords hate to throw clear readable codes****

If it's not the PCM, it sounds like it might be a throttle body issue. Maybe the throttle body position sensor. Mine went bad and I had very similar symptoms.

I_killdeer2

Ok thank you, gonna give it a go in the morning

JCooper

If by chance it is the throttle position sensor.... keep I'm mind, I think a whole new throttle body w/sensor is only a little more $ than a sensor alone. Good luck.

ProZach

I'm pretty sure that's only if you have an 04-05. 06-08 was supposed to be more reasonable of a cost.

JCooper

I have a 2006, but I looked up the parts at NAPA and they are the same part #s for both 2004 and 2006. I think I got mine (Motorcraft) from Sunrise Ford Parts through eBay though. Anyway, the prices that I found at the time were not too far off... it was a no brainer. There's a bunch of different sensors though... seems like maybe for different fuel systems? Not sure.

tmoods

Had the same problem with my 04' 5.4l for the last 3 years... And having a good buddy who is a mechanic has seen the issue with many different fixes included! We tried installing a new MAF on my cold air, new fuel filter, and a few different small things with no luck on fixing the issue. Luckily I purchased a edge evolution diagnostics display/ chip and one of the amazing features it has is alerts and high/low points of rpms, intake temps, oil pressures, ect. aswell as full display of gauges showing the current state of how our trucks running! Anyways going through a drive-thru at Tim hortons I noticed while in drive when pushing the throttle to move up and then letting go of the throttle right away my rpms would erratically drop down to 456. Got looking around the internet and found most 5.4l's should run, while at idle, any where between 570-640 depending on elevation/ atmospheric pressure where you may live! When the truck stalled my chip instantly showed an alert/ code that said, same as the one mentioned, unexpected low idle! So while dicking around with my chip settings I noticed I could change the idle rpm and decided to bump it up 70! No real reason for that number but my chip had showed my high and low rpms at idle so I took the average of the two, which was around 605 I believe, and added 70 making it 675! Been driving it around for 3 months have haven't come across the problem since!

Will Willard

I'm having the same problem with a 2006 f150 4.6 liter. Mines been doing this for years, and I've tried relearning the battery so many times I cant keep count. I've cleaned the sensor where the air cleaner is. I've cleaned one of the crank position sensors. It does the same thing as you guys trucks do. It dies at stop signs, surges when backing out of driveway. Dies when I suddenly slow down, all the same crap. You would think by now someone would have figured it out in 10 years. I keep coming to these forums year after year thinking l will find the answer. I see some of you have 2004 trucks, here we are in 2014 and people still chasing this ghost, WTH? Ive been told its the crank position sensor. It through a code and did say something about the crank sensor and also unexpected low idle/rpm. from what I understand the 4.6 has 2 sensors/ one on each head. The one by the driver side is easy peasy to get. The other one on the passenger side you have to jack up truck and crawl under and remove the air conditioner compressor, Wasn't that just kind of them? If anyone ever figures it out I hope they come back here and let us know what it is. I even had a man at the dealer ship tell me I had the wrong battery. He said the OEM battery had some special electronic boondoggle built in to it WTH? Who knows.

Especial86

iTrader: (1)

This is the answer^^^
Worked like a charm for me too.. I haven't stalled once in the 3 years since I raised my low idle on my tuner.. I raised mine 50 rpm's and that was all it took..

ProZach

I too used my programmer (edge) to bump up idle to prevent stalling. I was just worried there was an underlying problem that wasn't being addressed while I was operating that way.