As it turns out, replacing the "crankshaft timimg sensor" DID NOT fix the rough idle problem as I posted on 10/15. The L did run smoother when it left the dealership...next morning cranked it up...SAME rough/twitchy/random shake idle. On 10/16 back to the dealer...ran diagnostics AGAIN...no computer errors...then the Service Manager got involved...said he would call an engineer at SVT to discuss the problem and what else to do. On 10/17 went back to the dealership to speak with the Service Manager to see if he gathered any further info from SVT....
The Service Manager said the SVT engineer (Tom Jenkins) responded with the following comments:

1. They don't know how to fix the rough idle.
2. There are 17 documented cases of rough idle with Lightnings.
3. They think the problem is air/blower related and NO fix available yet but under investigation.
4. Ford wasn't particularly worried about it since it was just occuring at low idle; not at normal running RPM.
5. SVT did not think the engine was actually physically "missfiring" at idle; just gave the missfiring symtom.


So I'm obviously stuck with a rough idle...other than this, the L runs great. I've even changed from
Amoco premium to Texaco premium, just to try anything. Also note that the fuel filter is changed every
8-10k miles. Any of you have any suggestions?

 

Things to look for--in order of likelihood:

1. Vacuum leak(s)
2. Leaking EGR valve or plugged PCV valve(unlikely, IMHO?)
3. Air filter clogged
4. Fuel pump not delivering sufficient fuel.
5. Leaking head gasket.
6. Timing chains worn.
7. Valve(s) burned

Hope you get it figured out.

Dan

 

LIGHTNINROD:

Thanks for the advice Dan.
I'll change the fuel filter and PCV valve this week just to eliminate
those as possibilities. The dealer told me this morning that they have to have a "clear" suspect part before they will replace it.
They told me that defective parts are sent back to Ford for analysis and if it's not "really" defective Ford will chargeback
to the dealer...hmmm...then I guess Ford is receiving many thousands of returned Ford defective parts a day. How could they possibly analyse all these parts?!...I think the dealer simply
does not know what else to do about this idle problem.

 

The dealer hangs on to the parts for about 3 weeks in case
Ford wants to see them, and then can discard them. They do
not return ALL warranty parts to FORD. (My God that would be
expensive !!!)

I have noises and low idle bangs and whistles that we have
been chasing almost since Day One ... Replaced everything
in front of the firewall including the supercharger, and it still
happens at low idle speeds. (I must be one of the 17, cause
I pitched a fit!) $33,000 for a truck that won't idle is absurd.

Someone, somewhere knows how to fix these thimgs, we
just need to FIND them .....

Cliff

 

SVT_KY:

Prior to the last 4-6 months the L had a fairly normal idle.
My truck gets the best of care and is fully stock...after the
rough idle developed the dealer has replaced at no charge
MASS, plugs, airfilter, two IAC's, crankcase timing sensor etc.
When the engine is at idle you can SEE and FEEL a random
engine shake or twitch. If the hood is open you certainly
can see the random slight engine shake (like a missfire).
The 5.4 engines are known for odd/rough engine idle BUT the
dealer service manager stated that this problem is more visible
in the Lightnings. Some of the better techs or engineers at Ford
surely must have a better understanding of this problem. It
upsets me that this truck wont idle properly...it makes me wonder
if I should ever get another L (this is my 2nd one). Thanks for responding Cliff. The dealer (this morning) offered to run diagnostics again but dont think they find anything different.
I watched the tech run the diags through the service port and
believe he was professional and skilled. Cliff, mayby you and I
are number 17 and 18 of the documented cases.

 

Bad coil pack caused this on mine. Did not throw a code. Dealer replaced them all. Fixed.

Steve

 

Have you checked the O2 sensors? And then I would look into the injectors. Worst case.....hydraulic adjusters in the valve train.

I've always thought the engine in my truck was the smoothest thing I've ever owned. Maybe I haven't owned enough cars.
Dale

 

Calightnin:

I repeatedly asked the tech about the coil packs...he said
that the "missfiring" was random...if it was a coil pack or packs the missfiring would show up at the same plug or plugs on the engine analyser...I watched the firing graphs myself and it was indeed random...
Thanks for the info.

 

IAC maybe. I remember some post with guys saying they had a rough idle, cleaned the IAC and everything was fine after.

 

Bad as L:

The tech "said" he checked the O2 sensors and fuel injectors and they were ok. The engine DOES NOT throw any error codes...
This makes troubleshooting more difficult since you have no error
code to work from. Thanks Dale for responding.

 

2001SVT:

Iv'e had the IAC replaced months ago...it did help for a short while. They also replaced my plugs at about 23k miles and they looked normal.

 

maybe someone tried to play a trick on you and swaped the cams on you jk

 

If the misfiring is indeed random, perhaps something (sensor) is giving intermittant bad info to the PCM. Or perhaps the PCM is the culprit. Have they reflashed it?

Mark

 

Ak.Silver2K:

"perhaps something (sensor) is giving intermittant bad info to the PCM. Or perhaps the PCM is the culprit. Have they reflashed it? "

Good point...the PCM has NOT been reflashed but is up to date.
Bad data from the sensor to the PCM would cause all kinds of buggy, witches brew of problems. Today I'll clear the PCM just to eliminate one more possble source of problems.

 

I was going to suggest disconnecting the battery to see if 'clearing' the computer would help.
If the techs at the dealership can't find the problem, sure as chit my dumbass can't help ya
What type of plugs do you run Georgia Moon? Maybe you should pull them out and clean them in a solution such as this.............