I have the 01 F-150 S-crew with the 4.6.
Truck started doin the herky jerky not long after we got it just over a year ago. Shop couldnt find problem. Did new fuel filter and injector cleaner. seemed to do it. A few months ago, it started again. Injector cleaner worked. Then a few weeks ago, did it again. New fuel filter. Changed plugs for 1st time since getting it, as dealership said theyd done new. Plugs were rusted in, so the dealership lied. It worked for about 2 weeks and then started shaking a bit, not as much as before. Then two days ago it did it again hard-core. Checked the plug connect, batt connect, alt and alt plug connect, MAF 'appears' okay, so all good. Still jerking. It surges, and now at idle I can go down my street at 15mph, before I got 8-10mph at idle.
Also wondering what the sensor is called that is between the MAF and intake manifold? Could it be problematic? Cant afford the cost the shop wants for a scope run.
Also should mention, its not a bolt thing. Front end rebuilt a while back and all bolts currently check out.
HELP, its our one dependable means of transpo in the family.

 

Sounds like it could be a COP. Did you change those at all? The plugs might have cleared it up if one was starting to fail, but it won't last long and it'll do it again. I had a similar issue - although it is hard to tell from your post when exactly it bucks/jerks - and a new set of COPS did the trick. LOTS of threads on here about COP failure - just search the forum and read up to see if the problem matches what you are dealing with.

Might give some more details about when it bucks, under what driving conditions, etc.

 

Okay, call me dense if you wish, but what exactly is a COP?

 

Recommend you begin learning quickly if your going to do the work.
COP= coil over plug, not coil pak.
Get the plugs changed in the proper manner with good boots and grease, then if you still have a problem, a coil may have shorted turns causing the missing problem at light throttle loads.
Do not use additives in the fuel to try to solve this issue. It's not the cause nor the way to solve issues.
Get a service book at your local auto store before you begin.
Good luck.

 

I thought that might have been what it meant, but wasnt sure.
Will look into that in the AM.

 

Does fine for a few miles.
We live in a rural area and have to get on the freeway to go into town. I get a bit on the freeway (about 4 miles from home) and it starts jerking, no matter the speed. Other than that theres no rhyme or reason to when it does it. It will do it at 30mph or 75mph. It surged from 30 to 35 right in front of a cop last night! It doesnt do it at first when Ive stopped at a store or something, but if the hoods still warm, it happens much sooner.

 

How many miles on the truck ?
Does it Buck/Jerk more when the engine is pulling (working) harder ?
Wet outside or what ??

My son has an 01' F-150,,when we bought it ,,,the seller also had a set of Motorcraft plugs,,and Motorcraft COP's he had purchased for the truck to do a tune-up,,Good thing we got them too,,,after a few miles he said it bucked and jerked when pulling a hill,,worse when it was damp out,,,we got around to changing COP's and plugs,,,using dielectric grease in the cop boots,,a dab of Never-seize on the plug threads,,,torqing them to spec,,,what a difference the truck runs Great now,,,!
This F-150 4.6 now has over 201k miles and the engine sounds and runs Great.

 

There are no dense questions. Always something to learn in this field.


Our new Ford COP’s, the Sultans of Spark(S.O.S.), have
been designed with both durability and performance in mind.
Please see them at:
http://www.performancedistributors.com/soscoils.htm
Quality was the main feature we stressed when we went to the
drawing board on these coils.
See your FTE special at:
https://www.ford-trucks.com/forums/793806-cop-fte-special.html#post6780133

 

A little insight on coil design.
The wire is usually enamel coated copper.
It is usually wound on a Toroid core (round) form at a specified winding tighness.
After completion and in service, heat makes the winding and core expand and contract.
This raises the possibility of wearing through the enamel coating at some point along the winding.
Since it only takes one turn to short, it lowers the output voltage because the effects a shorted turn has on the magnetic field around the core, is large.
The total effect on winding resistance is small and usually not detectable by an ohm meter test unless the short occurrs accross many turns, then this would be a total missfire failure and detectable by normal PCM diagnostics.
This peticular missfire condition occurrs only during the time that EGR is invoked usually during OD light loads.
Reason is at this time the air to fuel ratio can be upwards of 20 to 1 a very lean mixture that requires much higher voltage from the coils ( called reserve voltage ).
If it is not available a missfire occurrs at those instances.
Along with all this, when the EGR routine is called, the fuel injection amount is cut back (leaned), the EGR is opened introducing exhaust gas causing more leanness and ignition timing is advanced.
If the coil for even one cylinder does not have high enough output a missfire occurrs.
To make matters worse, this kind of issue can send noise and other undesired signal back to the PCM upsetting total processing for nearly all other functions until recovery takes place. Often this will show up as if the ignition key were momentarily shut off then back on when the PCM recovers. This causes a huge 'BUCK' while driving.
Since this is NOT a permant failure, the PCM does record it in temperary memory but soon clears it out when the EGR routine is canceled by application of more throttle, down-shifting and speed/larger load changes as richer mixtures occurr and need less voltage the coil can now supply without a missfire and the problem goes away until the next time the conditions are entered..
At this version of the PCM program (now obsolete), it cannot detect on a 'logic failure' basis and set a code because it was never anticipated by the software/hardware designer.
As a last hint, often new spark plugs will aleviate the issue for a short time as the new plugs require less voltage to fire the same mixture until they get 500 or more miles on them and begin their aging process that raises the voltage requirement as well.
This is the only explanation you will see on this issue because few have put it all togather in this manner.
.
Some aftermarket coils are wound on a straight cores, making the total package a different shape but can always be subject to the same type malfunction.
Making coils bullet proof cost more money in time and material as well as workmanship so take that into account for coil quality that you may not be able to asertain at any time.
Mass production always brings with it the element of luck for the consumer in order to keep the cost down.
So changing them en mass sometimes causes confusion when a new coil might also be defective making it pay to find the bad coil instead of chasing the problem endlessly over a long period and spending more money than needed.
Remember this reply to the issue for future reference on any reports of bucking during light throttle in or out of OD.
Hand a printout to a tech or servicer for such issues and ask for a coil stress test to find the low output coil.
It costs extra but gets the problem right away unless 8 good coils are installed the first time around. If a dealer has a bad coil in stock, your in luck for warrenty on it if you end up with it and it fails in a short time.
Good luck.