shake/shudder at low RPM (mostly after immediately shifting in to OD at around 40mph)
 

My 2001 F150 5.4L XLT SuperCab (automatic transmission) has had this problem since i got it (about 8000 miles ago.) It has progressively gotten worse and worse, little by little. Just to give you a good idea about what is happening, I will give an example. Let's say I'm driving on a level road going about 35. I slowly accelerate without any problem to 40 mph. Once i reach 40 mph, my truck shifts to 4th gear. i maintain this speed with extreme minimal throttle. If i try to accelerate just the slightest bit, the truck begins to shake. If I go ahead and give it about 1/2 throttle, it will downshift and smoothly accelerate without shaking. However, if I don't give it more throttle or if I begin up a small incline/grade, my truck will shake madly. In other words, if I drive at 40 mph, with just the right throttle pressure, My truck will shake constantly. Torque Converter? Fuel Problems?

Please give insight, Thanks.

Does it feel like a bucking more or less when you hit 40 to 45 in overdrive? if it does i had that issue and i had a cop crapping out when the truck was hot mostly but not enough to throw a code i found a cop cracked on top and it even ohm,d out good as well also i did the plugs at the same time and it fixed my issue

Drop the trans pan and Change the trans filter and fluid. My shudder was gone after I did that

By cop, do you mean coil?

I would start by checking the cop (coil over plug) my expedition had the same problem at low rpm.

Yes you have eight of them that sit right next to each inj. that are right below the fuel rail with some patience you can get in there and take a peak at each one and also check the connections as well they are usually black and round have seen some high performance one that are yellow to next to the usually yellow injectors your plugs are about 4 inches below it hope this helps

jbush,
there has been a lot of threads about your problem.
Look some of them up.
Your issue is a faulty coil with shorted turns.
You discribed the drivability issue perfect.
Now here is what you feel.
At about 45 mph the trans upshifts to OD.
Next the EGR is called to open 'under light throttle'.
What does this do? It causes the air/fuel ratio to become very lean in the 20 to 1 ratio range. The coils have to have reserve voltage to fire these lean mixtures. If not, you feel a missfire.
As you found, as soon as you add more throttle opening, the ratio goes leaner yet until a forced down shift occurrs with enough extra throttle opening. The EGR closes again and the faulty coil will now function ok and the missfire goes away until the next time you enter the same driving point again, it starts all over again.
What is the problem?
It is a coil with 'some' "SHORTED TURNS". this is not considered a 'hard' fault by the computer because the problem goes away when you force or decell a downshift.
Besides the computer will detect any coil with an open winding or circuit as the cylinder will not fire at all and is a hard fault for which a code will set.
Problem is finding which cylinder it is because there is no code record you can see easy without a good scanner to look deeper into the the program where you ' might' see it's record.
This type fault has nothing to do with a transmission fault unless it is a coincidence that both are present at the same time and rarely ever happens.
Good luck.

I am having the same problem with my 99 xlt and after hours of reading andnion comparing the codes I have pulled 0301 and 0351. It sounds like cop. Bluegrass 7 has comented in a lot of threads and in my opinion he knows the symptons to a T. I am gonna change the plugs clean and or change the boots and change the cop in question. Will let you know my results. Great forum btw! Help yourself help another!

A small addition
 

He is absolutely correct about the coil but I have just one more addition to his post. I had the exact same issue with my truck and after an exhaustive search for the cause to this problem I found that there were a couple of bad spark plugs. The truck seemed to run ok until the upshift as mentioned above then the shudders and bangs started.

After checking out everything that could possibly cause this I changed the plugs from the aftermarket plugs to the Ford plugs (very expensive) and the problem was gone!! I informed a buddy who is a tech at a Ford dealership about this and he said he never heard of it. Then about 7 months later someone came in with this problem and one of the other techs was given the job.

He gave up after a day of searching for the problem and my buddy heard about it, so he changed the plugs after remembering what I told him and it floored the other techs when it ran like a top again lol. Big hero lol. Anyway just an FYI for you and others in case the issue wasn't corrected yet.

When I first came on this board, I saw a lot of posts discribing this drivabilty issue and no one had an answer.
It is always possible to have more than one issue at a time causing confusion.
Poor boots, old plugs aggrivate the issue further.
One has to have that thought in mind along with looking for the root cause that just one issue is all there will be, is setting up for a failure to complete the repair.
Years ago I had the issue and went with it for months trying to figure out what caused the stumble only in OD at light throttle and almost no other time.
A study of what other systems are doing at that time began to tell a story I really understood but never put all the pieces togather.
My digital monitor also was telling me something was causing the ignition timing to go retarded even to the point of going -2 degrees at the same time the stumble occurs.
Putting it all togather involved the mixture. A/F ratio is going very lean at over 20 to 1 from the normal 14.6.
What does this do for spark voltage requirements?
At over 20 to 1 A/F, the voltage requirements go up dramatically to fire that lean a mixture.
If no cylinder code was set indicating a hard fault, it must be a coil with shorted turns but which one?
The hunt began. First replace plugs. Was a help for about 500 miles then the stumble came back.
What was this? The new plugs are easier to fire even by the faulty coil until the plugs began to get erroded making voltage requirements go up to where the coil again could not fire the cylinder reliably.
Lesson; plugs do influence the cylinder combustion reliability but was not the answer or the cause.
Replace plugs a second time with the same results.
Advancing, it has to be a faulty coil on one cylinder.
Replaced the whole set and problem cleared but which one was it?
Finally went through all the original coils one at a time in cylinder 1 until the problem returned.
Next was to set a scanner up in trap mode to freeze frame the data and cylinder involved. It picked out #1 cylinder.
As time went on I lost more coils to both the stumble and hard codes.
The only answer to the stumble is the coil winding developes shorted turns from the repeated heating and cooling cycles they go through.
The wire is enamel covered copper wound on a bobbin core.
As they heat, the wire goes tight from core expansion and wears through the enamel coating. This can also break the wire at the connections causing a hard fault and a code.
Back to the shorted turns; when this happens the magnetic field around the core is reduced and causes lower voltage output hence the stumble under the specific driving conditions and very lean mixtures.
There is more science to this involving cylinder combustion, the PCM and other effects but we will stop at this point.
Hope it is of value understanding the problem.
I know most are not interested in the involved explaination but just want a fix but there are others that need a better understanding of this issue and how to get a handle on it faster.
Good luck..

[QUOTE=Bluegrass 7;12601908]When I first came on this board, I saw a lot of posts discribing this drivabilty issue and no one had an answer.
It is always possible to have more than one issue at a time causing confusion.
Poor boots, old plugs aggrivate the issue further.
One has to have that thought in mind along with looking for the root cause that just one issue is all there will be, is setting up for a failure to complete the repair.
Years ago I had the issue and went with it for months trying to figure out what caused the stumble only in OD at light throttle and almost no other time.
A study of what other systems are doing at that time began to tell a story I really understood but never put all the pieces togather.
My digital monitor also was telling me something was causing the ignition timing to go retarded even to the point of going -2 degrees at the same time the stumble occurs.
Putting it all togather involved the mixture. A/F ratio is going very lean at over 20 to 1 from the normal 14.6.
What does this do for spark voltage requirements?
At over 20 to 1 A/F, the voltage requirements go up dramatically to fire that lean a mixture.
If no cylinder code was set indicating a hard fault, it must be a coil with shorted turns but which one?
The hunt began. First replace plugs. Was a help for about 500 miles then the stumble came back.
What was this? The new plugs are easier to fire even by the faulty coil until the plugs began to get erroded making voltage requirements go up to where the coil again could not fire the cylinder reliably.
Lesson; plugs do influence the cylinder combustion reliability but was not the answer or the cause.
Replace plugs a second time with the same results.
Advancing, it has to be a faulty coil on one cylinder.
Replaced the whole set and problem cleared but which one was it?
Finally went through all the original coils one at a time in cylinder 1 until the problem returned.
Next was to set a scanner up in trap mode to freeze frame the data and cylinder involved. It picked out #1 cylinder.
As time went on I lost more coils to both the stumble and hard codes.
The only answer to the stumble is the coil winding developes shorted turns from the repeated heating and cooling cycles they go through.
The wire is enamel covered copper wound on a bobbin core.
As they heat, the wire goes tight from core expansion and wears through the enamel coating. This can also break the wire at the connections causing a hard fault and a code.
Back to the shorted turns; when this happens the magnetic field around the core is reduced and causes lower voltage output hence the stumble under the specific driving conditions and very lean mixtures.
There is more science to this involving cylinder combustion, the PCM and other effects but we will stop at this point.
Hope it is of value understanding the problem.
I know most are not interested in the involved explaination but just want a fix but there are others that need a better understanding of this issue and how to get a handle on it faster.
Good luck..[/QUOTE

I understand your research and work to find the problem mentioned in this post was a lot of work and I'm sure you're absolutely correct but after I replaced every coil with OEM coils the problem persisted. It was after I replaced the plugs that the problem stopped and it's now been almost a year with over 20,000 km and it's still running great. For this reason alone I decided to post what had finally worked successfully for me after spending a fortune at the dealership with no success etc. If the same thing works for someone else without spending so much money then I'm happy to have helped out.

I would venture to guess that most people that go through the time and expense of changing COP's would also change plugs...using OEM plugs.

Plugs
 

I was told by the dealership that the plugs were new (I purchased the truck only a few weeks before the issue started), and to not bother changing the plugs because they were expensive and they doubted that the plugs would make any difference. I should have just done what I wanted to from the start but they are supposed to be the experts right? Well so much for that, next time I do my own diagnosis and if that fails then I'll go to them. I would have saved a lot of money if I had. Any other questions or comments? I never claimed to be a tech, just that I found the problem myself after the supposed experts couldn't solve it, and thought that I should tell others what I found. If this isn't good enough then fine I'll leave my findings to myself and let others pay the way I did! Enough said!

dude, you have 6 posts on here, don't get all sensitive on us already.
I didn't mean for you to take offense....wow.
I think they have "Thicker Skin" in aisle 7.

Respectfully, sometimes people from other countries see things differently and have different attitudes.
good luck.