I also posted this in the Lightning forum but this rough engine idle
occurs with many 5.4 engines...so for many of you that have tried other unsucessful fixes this may help.



For the last 4-6 months my 01 L (26kmiles, stock) has had a constant rough, notchy, twitchy idle. Numerous visits to the dealer resulted in a new MASS, plugs, airfilter, IAC (all under warranty). These fixes seemed to help but the problem remained unresolved. The L has run fine except for idle (neutral, park or drive). So this past Monday went back to the dealer and asked them to look at this idle problem again. A super nice SVT tech came over and watched the truck idle...said the idle was too rough and not ACCEPTABLE...took it immediately into the shop. He did the the full set of Ford diagnostics through the diag port (I watched)...finally when he got to the oscilloscpe type firing graph...could see "RANDOM missfiring"...He said it wasn't the coil packs or plugs or O2 sensors since the "missfiring was irradic or random"...if it was a coil pack etc. the missfire would be at the same plug or plugs...the Tech suspected the crankshaft sensor and the part was ordered...NO computer error codes were indicated during any of this testing...he said that the microsecond timing of these "missfires" were too small and fast to be picked up by the computer and logged. So today, took the L back in (part came in)...the Tech had to remove the AC compressor to get to the "crankshaft timing sensor". Replaced the sensor...cranked it up...MUCH smoother in idle...
Evidently this sensor (same as on all 5.4 engines) was the problem but time will tell as we all know. Even though NO scan code errors were given, the actual realtime firing graph pattern told the dirty story...Hope that this might help some of you with similiar idle problems...the Tech did comment that these engines will not idle "dead smoothe" but too rough of an idle is another issue. Will let you'll know if this is a permanent fix.

 

Cool. How much does that part cost? For those of us not under warranty, this could be very expensive (labor).

Another thing I have always wondered, how do you tell the difference between an idle that is too rough, and a "normal" idle?

On mine it usually idles pretty smooth, but sometimes it gets kinda rough. Its hard for me to scale it really, so is there some way to tell?

Thanks, and keep us updated

 

Johngs:

I'm not sure of part cost but probably less than $50...but will find out for sure.

Well...one of the oldest and a good test is to take a glass of water (glass is more vibration conductive)...place it safely somewhere on the engine...see if the water level shakes the same or irradically "twitches or periodically shakes"... mine was
a rough continuous idle with irradic "shakes"...the shake is actually a rapid drop or increase in engine rpm.

About the only way to truly "see" a rough idle is with an engine
scope/analyser that will show you in real time all the plugs and fuel injectors firing or being triggered. Hope this kinda answers
your question....,,how smoothe and even the plot or graph is
is indicative of a fairly smoothe or rough idle.

 

Hmm, I think mine would fail the water test when it gets the rough idle.

But, wouldnt you know it, it never gets the rough idle when Im at home in the driveway, trying to get it. Its always on my way home from school, or something like that.

 

unless you're an extremely experienced mechanic, take it to ford. ford uses a special tool to line the cam up with the pistons and all that stuff. this is a pretty precise procedure, and from what i understands runs from about $250 to $300 with parts and labor.

 

The rough idle is really driving me nuts.
Actually I did that with a glass of water, 3 weeks ago.
I put it in the cab, on top of one of my rearwheels and on top of the box near my taillight.
Quite a lot of shaking going on.
Shot some videos, see if I can get them posted.

Idle Ford Rough

Thanks for posting.

 

Georgia_Moon,

Read in the Lightning section that you had no luck with the new sensor.
Shot a vid this afternoon of the rough idling I have.
Is yours less, the same or worse.
Maybe other members can test this too and let us know here.
I just put a glass of water on the throttle body cover with a piece of paper under it otherwise the glass would slide of the TBC.
The camera was not mounted on the truck, it was steady all the time.

The vid is showing 3 minutes of idling in P with a warmed up engine. Engine is a 1999 5.4 liter, no mods, plain stock.

The wmv file is about 5 Mb so it may take a while to load.

My rough idle

What do you guys think of this engine's idling?

 

F150Europe:

Hi....I'm really impressed with your creativity with taking this video...well done !......seeing it and hearing it really helps in understanding. It was also clever to not mount the camera on the
truck. How did you convert the video to .wmv?....I need to do the same thing...(I have a digital camera that can take 30 seconds or so of video/audio)...then we could compare and others may examine too.

Actually F150Europe, mine is worst...most of the idle is "somewhat" like yours but then it will randomly (significantly)twitch or shake. Yours does shake but not as pronounced or
marked as mine...mine is almost like a "shutter". Today I reset
the PCM...so Monday will let it relearn the driving parameters...
I'll post the results but I don't expect anything positive.

Have you reset your PCM?

 

My camera is recording avi files. The one you see here was like 57 Mb. I use Ulead Video Studio to convert to wmv files.
But you can also use the Movie maker in Windows.
You have to look what the best settings are, though.
The size what you see, quality of the sound, framerate, stuff like that.

Like most of us here, I have done a lot to ge rid of the rough idle.
To exchange all parts for new ones is a bit expensive here.
IAC,EGR,DPFE etc....

Resetting the PCM won't help either.

I can't live with it though, it is very annoying.

I will post another vid taken in the cab.

Thanks for replying.

 

Have you ran SeaFoam through the thing?

Carbon build up will cause plenty of problems in the idle department too.

tom

 

My idle is the same or worse than the video.

 

F150Europe:

Thanks for the tip on Ulead.
Yesterday reset the PCM...this morning (Monday) cranked
it up...same thing...twitchy sloppy random spike idle.
This has me really fustrated...I called Ford in Detroit...
They are to call the dealer to decide on the next course of
action. I understand your annoyance with the problem.
You have a nice website...interesting.

tkarter:

No, never tried the Seafoam...but may consider it if all
else fails...thanks for the suggestion.

PacNWBlueOval:

It looks like a lot of people are having the rough idle problem.

 

I had some spare time today, so I shot video of mine as well, plus I get to play with the camera so why not :P

(~5mb each, .avi)
#1 (30 secs)
#2

If they dont play automatically, you can right-click and save as to view them.

The water doesnt shake much in mine, but the glass does a fair bit of moving. And I think this isnt the usual "rough idle" that mine has at times, sometimes it is worse (feels like it in the cab anyway).