Thanks very much for this thread. I have had a consistent highway shudder/clunk in that 80kmph range in the last year or so. Thought maybe the ujoints or ubolts for leaf springs were loose and causing issues. Then I read this thread. Replaced the plug wires on my 4.2 v6 with 335k km and the problem is gone. Thanks again.

 

66,311 hits on this thread's subject.
It is a very common issue not well understood even by most shops.
Good luck.

 

I wish I knew it was such an easy fix. I knew that I needed to do a tune up anyway, but if I would have known that 3 coils were weak I would have done that after the first time the shuddering started instead of thinking that my transmission is going out. live and learn I guess.

 

Don't feel bad Kevin, I was in the same boat. Luckily I had a couple of ex-Ford techs working on my truck, and they suggested because of the trucks age and unknown maintenance, to just replace all the COP's. I know NOW since reading more about how Bluegrass explained everything, what was going on. I most likely did NOT need a full set, but purchased them anyway. This is my sons truck, and like his two sisters before him, in my house you only get ONE mom and dad purchased car. The next one is on YOUR dime, so when I have purchased kids vehicles, they go through a complete tune up, fluid change, a/c charging to hopefully make sure they last 3 to 5 years after high school. The next set of COP's, if needed, will be on his dime.........

P.S. I want to personally thank Bluegrass 7 for his input. If you understand the workings of an engine, his breakdowns are spot on with what is happening to cause the situation. Thanks!!!!

 

yeah, you were lucky that you had ford techs, but it is pretty sorry that they made you replace all of the coils instead of just the ones that it really needed.

my parents only bought me ONE vehicle to drive, now I have to pay for all the gas/repairs by myself.

 

A little update on my V10 motor home I bought the MH and drove it 150 miles back home, Bucking and Jumping and Studdering all the time. Over the course of the next couple of weeks I took two short trips to get other maint. Both trips were about 25 miles and a week apart. Still lotsa BJ&S.
Made appt with repair shop and drove 50 miles last week. Started to BJ&S right away, but as soon as I got a couple of miles down the road it SMOOTHED OUT AND RAN PERFECTLY for the rest of the trip.
The tech drove it and COULD NOT TO GET IT TO BJ&S any more…
He looked at it with the scanner for about half hour and determined that COP 2 & 9 were bad.
I opted for a regular oil change service along with fuel filter, spark plugs, and a B&G engine cleaning system.
Drove it back home yesterday and everything is OK and I’m out $1400 bux.
Thanks again to Bluegrass and others who opined here. Feels like home already…/gene

 

awesome! hope all goes well

 

Same problem for me. I took it to the dealership and they said it was the torque converter which they changed out. Firtunately I had the ext warranty or it would have cost $1,700. It fixed it for a year or so but now I am noticing a slight return of the shudder..

We'll see how visit #2 goes..

 

Your studder is very easy to find.
It's a faulty coil.
Ask them to use a Scanner and look at the misfire monitors for each cylinder.
It's found in mode 6, test 53.
Step through to each cylinder and look at the counts.
The one with the high counts has a faulty coil.
It was never a converter issue.
Good luck.

 

Big thank's to Bluegrass7 and other posters, my 2004 freestar 4.2l was doing exactly that and when you search the interweb you only find horror stories about transmission problems,

what is described as jerking/studdering is exctly what's happening to my freestar and what is explained to solve it is such a releif, i was ready to give up on that van, trans is worth as much as the van...thank-you

I will make check on coil packs tomorrow and let you know the results

 

As promised here is a follow up on my van's problem.

I had the jerking like many experimented, in the mean time i also sporadically had bearing noise coming from the belt area. changed the alternator, bearings were worn but noise was still coming time to time, since heating was no performing very well i planned to change water pump .

and while doing research on noise i found that.


It's exactly my noise. Changed the cam synchronizer and BINGO. No more jerking and misfires, did not change any coil packs or wires (they are oldand due) , plugs are from ford and have about 20k miles.

Did a test drive on hyghway on rainy conditions and all is well.

Hope this can help.

 

Remember, for those reading this old and long thread, the 97 to 03 model years do not have cam synchronizers on the 4.2, 4.6 or 5.4 motors within the year range.
Good luck.

 

sorry about my posts misplacement . this forum is so big and i have been led here only by the symptoms that matched.

If a moderator could place it in a better more appropriate location, please let me know and i will post there in the future.

thank's Bluegrass7

 

I have an 03 f150 4.6l with p0302 code. I have replace plug swapped cop new plug boot and new injector. Any other ideas that might cause this problem.

 

I have a question. We have changed the number one coil and spark plug because my scanner said cylinder one misfire. It was good for one day with the check engine light off. Still slight shaky. But it is back on and blinking when we are driving and it really is not well when we are around the 55 mph mark. Do you have an idea on what is happening. I have a 97 ford expedition. 4x4