You need to keep chasing the issue with a Scanner to be sure there is not more than one issue at the same time or even if it is the same cylinder.
If the same cylinder, obviously you did not get the initial problem.
Misfires of this sort can be a plugged injector, a coil, a boot, intermittent connector, intermittent harness lead or even the coil driver in the PCM.
Be sure you look at mode 6, test 53 at the cylinder misfire monitors for each cylinder.
Be awhere that in a marginal misfire condition a new spark plug might clear the miss for a certain number of miles then begin to miss all over again.
Why; the new plug with sharp edged electrodes makes it easier to fire a charge until they begin to erode, then your back to the original problem again.
Normally there is enough spark in reserve to handle eroded plugs well up in the higher thousands of miles as long as there are no faults in the system.




You have no other option than to renew the search for the problem.
Good luck..

Hey Bluegrass, I have read this whole thread and am taking your advice of using a scanner and finding the one that is missing. However, the Craftsman 20890 is discontinued and I am having a tough time finding a scanner that has the "trap and freeze function". Would you happen to know of any off the top of your head? Innova 3150 or 3040 do the trick? I am trying to be in the -$200 range.

Thanks again!

I've never heard of a scanner that does that. Neither has Google, I asked.

When a fault code is stored, the PCM also stores a set of readings calle the "Freeze Frame" data that gives certain particulars abut the operating conditions at the time the fault was registered.

To diagnose an intermittent misfire you need a scan tool that can read Ford's Mode$06 data. The PCM stores accumulated misfire counts for each cylinder (if it can determine it) and you can read that data and see which cylinder(s) is having issues. See these threads for more info: Ford Truck Enthusiasts Forums - Search Results

Thanks Project, I ended up finding the Craftsman 20890 NIB on Ebay for $140, I scooped it up. I am sure other models have the function I am looking for but the info in this thread regarding the craftsman is invaluable to someone not tech savvy such as myself.

Glad you found one.
Did not know they discontinued that model. Must have just happened recently.
You can either use the trap function or look at mode 6, test 53 to see the cylinder with the counts out of limits.
The trap function will ask you if you want freeze frame info before the trap, during the trap or after the trap. Choose the middle one during the trap so you see the cylinder involved.
Matter of fact this mode will show a cylinder in trouble before is gets bad enough to set a code.
Sometimes it's a boot or a coil causing the misfire counts.
All the cylinders could show low counts or none at all. If so and they stay low, it's normal and no action is required.
Every cylinder does not fire every time all the time for various associated remote reasons, just a fact engine of life.
Once you do a clear, these monitors are also cleared and take some time to build a count on an offending cylinder so have patience when chasing some troubles.
Good luck..

I'm experiencing the tug/jerk/shuddering in my 2012 Escape v6. It happens more around 70mph or 2,000-2,500rpm.


Tug/jerk/lurch/buck happens even more with OD off. Happens around 60mph or 2000rpm with OD off.


Been to the dealer several times even test drove with a mechanic that acknowledges the tug/jerk sensation. No codes or faults. Last visit the dealer showed me a print out of misfire counts and all cylinders were 0 yet on the drive home it was tug/jerk/lurching.


What could it be?


Bought a craftsman 20890 scan tool and read the entire thread here. Great info Bluegrass7!


I have the power graph printout as well. The line for each cylinder rises and falls almost like a sine wave, is that normal or should it be a flat horizontal line? I could scan and post the printouts if that would help?

Your 2012 has much advanced engine management.
The fault could be some other function.
This forum applies to 97-2004 model years.
There are great differences .
Good luck.

Bluegrass 7, I am having the same issue with my truck jerking and studdering around 50mph at times. However, I have a 1994 5.0 engine. Would the ignition coil be the culprit on my truck also?

Start with the basic tuneup stuff - plugs and wires. Your older 94 has only a little built-in diagnostic capability compared to the OBDII systems. IIRC, you can run a cylinder balance test with nothing more than a paper clip on that engine/computer combination.

If you can find a shop that still has their old SUN-type ignition scopes and a old guy who remembers how to use it, they can easily troubleshoot it.

Thanks Bluegrass 7
 

Had this issue on my 01 Sport Trac. Easy fix for me because I only have one coil pack. I went ahead and changed the plugs and wires while I was working on it. Thought my transmission was going out, but all is good now. Thanks again.

2002 F150 5.4L FX4 same symptoms with a P0340 code
 

Hello all. I've been experiencing the same jerking/bucking issue with my 02 Super Crew. I have replaced the plugs and COPs. I'm getting this jerking typically on the highway between 65-75mph. It has occurred at lower speeds 45-55mph. I have had the vehicle on a very good scanner while driving it and it is not picking up any problems or codes. It will occasionally throw the 0340 code. The CPS has been replaced to no avail. Any thoughts?

Use a Scanner to 'look' at the misfire counts for each cylinder.
Mode 6, test 53.
Do not wait for a code to set.
The code 340 is the camshaft sensor having an issue.
If it was replaced it may be the plug or harness.
Trust the code but don't just stop at replacing the sensor.
This sensor is the reference for fuel injection the computer uses.
Sometimes you have to go beyond the simple stuff.
Good luck.

I've a 1999 - 4.2l V6 with one coil -- can this be tested ? Thx!

Not in any meaningful way with anything you have to test with.
On your V6 it could be plug wires, crossfires, leakage to ground as well as the coil.
Look closely at the coil terminals for carbon leakage paths around the terminals.
Use a Scanner to take a look at the misfire counts as given above, for positive proof of misfires.
Good luck.

Thanks for the advice - Checked for vacuum leaks at and around intake manifold ( 1999 F150 - 4.2l V6 w/ 282k miles) is there a vacuum line to the transmission that I cannot see? It only shudders/misses under load... and no power to accelerate at all...