Hello Ford Truck Enthusiasts. I am a new member and have previously searched through many threads, without luck, on very, very similar symptoms I am experiencing with my 2000 F150 Harley Davidson edition. I don't think the edition is significant, I just want to be fully descriptive. The truck has 174,000 miles on it and runs and sounds just like it did the day I bought it, other than this inconsistent issue we are experiencing. While driving the truck at or above 40-45 mph, with light to moderate acceleration (no consistency), the truck will "buck" where the whole truck feels like it was just hit from behind rolling down the highway. The thing is, it is inconsistent, no check engine light comes on and it doesn't seem to do it when the cam position sensor is unplugged. I have had coil packs go out in the past, each time Ford dealer replaced. Most recently #4 & #7 coil packs and all 8 plugs. Since then I had Ford service try and diagnose symptom. On the way in check engine light comes on (fingers crossed). Took mechanic for drive and the bucking occurred. They pulled codes P0500 & P0340. After test drives, they reported "power balanced for #1 cylinder dropping randomly. Got harsh 1st-2nd shift on deceleration (i assume this is the bucking) several times. Checked plugs & coils-OK." So they decided with Fords approval that it was internal timing issue (ie. stretched chains, worn tensioners, ect. - mechanics words), they would just have to dive into the engine and see what they find for what could be up to $4,200. I remind you, the truck has gone hours or day(s) without doing it, while running like a champ in between, and it seems to stop when cam pos. sensor is unplugged. Could it be so very inconsistent and be mechanical??, could a cam phaser fail in a way that the symptom would be so inconsistent. I don't feel that this is a coil pack issue, Ford shop said they checked out-OK, I'm not sure if they "stressed tested" them. A second independent shop diagnosis returned the result of "it can't be the sensor or anywhere after the sensor because I'm plugged directly into cam pos. sensor. It must be on the other side of the sensor (or inside the engine). This doesn't make sense as he would still have to be connected to the rest of that circuit for the fuel timing, among other things, to run the engine during the diagnostic process, right? HELP!!!!
I drove the truck home with the cam sensor unplugged, a little sluggish and appears no bucking. Plugged cam sensor back in just before I got home. After truck set for a few days, I drove it for two days with the check engine light on (from the cam sensor being unplugged i'm sure) with no bucking whatsoever. After I got home from work on second day, I left for errand, no check engine light this time, it bucked within first 10 minutes, only two or three times though. Did it only couple of times this morning going t work, didn't do it once on the ride home, heaver on the accelerator that time. Don't know if that means anything.
Apologies for the long post, I am just banging my head against walls over this and I really don't think breaking into the front end of the engine or as Ford shop said, "we can drop a remanufactured engine in for just $1,400 more", is the answer.

Any ideas and suggestions would be greatly appreciated.

Trying to stay Ford Tough!

 

You still have one or more bad coils.
The cam positon sensor times fuel ,injection, leave it alone, the issue is not there.
This motor did not have cam phasers until about 2004 model year.
The chains are tensioned from oil pressure driven take up. Wear does not act random like that.
The 500 code was a VSS indicator, the 340 was the cam sensor. If they were not addressed but went away, the codes may have been a reaction.
You need to either replace all the coils or get a dealer to stress test them and honestly do it right as the first place to begin all over again to get the issue solved.
My feeling is your getting poor shop/dealer guessing advice.
How you handle it is up to you.
Good luck.

 

I am going to agree with Bluegrass here . I think o full set of coil packs would solve your problem . I have seen then act up randomly come and go but still not trip a CEL or even a pending code.
If you get a set off Ebay for less than $100.00 you may most likely will solve your problem and save more diagnostic time .

 

I am going to agree with Bluegrass here . I think o full set of coil packs would solve your problem . I have seen then act up randomly come and go but still not trip a CEL or even a pending code.
If you get a set off Ebay for less than $100.00 you may most likely will solve your problem and save more diagnostic time .

 

Sounds like my truck when a coil was going bad. I agree start out with a new set of coils, if you can't narrow it down to a specific 1 or 2. For the price of 3 at the parts store, you can have 8 off ebay if they are $100 like was mentioned.

 

Thanks for the replies! I will try replacing the coils as suggested. Is a shop the only place that can stress test coils?

Bluegrass, is there any significance to the point that the bucking doesn't seem to occur when driving while the cam sensor is unplugged? Would this still indicate a problem with my coil packs?

 

Unplugging alters the air/fuel ratio back to richer running.
A reaction to the missing sensor the program takes.
Reason: If a fuel table can be substituted in lue of a sensor, this is a way to keep the motor running safely instead of letting the driver set along the road needlessly until the fault has been repaired per the CEL code.
Same thing with OX sensors, if in operable, the PCM goes to fixed rich fuel tables instead of stopping the safe use of the engine until service is done.
What you don't want to do is continue to run the motor with one or more cylinder totally out 'per known codes' because it passes raw gas to the cats and will melt them after a few minutes. You don't want to know the dealer cost for that repair over and above the original cause.
As stated, the coil/s will fire the richer mixture because the voltage needed is not as high.
Also the faulty coils can be temperature sensitive because it is a 'shorted turns' situation not an open or dead short. This condition will set a code so there would not be any question as to the cylinders involved.
Shorted turns prevent full magnetic fields strength around the coil core thus lowers the max output.
You begin to see why it's difficult to pin point the coil/s that are the cause with no code to go with.
The no code is because the studder /missfire condition is not a hard fault so the PCM clears the count after it goes away.
I simply cannot see tearing into a motor or replacement at thousands of dollars with no firm proof without investigating the symptoms that point to faulty coils.
I may be wrong in all this but I am pulling for you, the best situation.
Good luck.

 

Makes perfect sense! I forgot to mention only 6 coil packs have been replaced, 2 are original. I will be replacing all of them though. Wont get them until Monday. I will come back with an update after change out and some test driving.

Thanks for being in my corner Bluegrass!

Thanks to everyone for your comments.

 

how old are they 6? You may get away with just doing the 2 original ones. I have 6 originals on mine at almost 180,000miles.

 

Welcome Daniel to FTE

 

I have to agree with everyone on this.

I have replaced the coils on my 97 5.4 so often I can do it in my sleep.

After about 5 years when I first bought my truck new in 97, I had intermittent coil problems.

The issue was that the Wiring harness was rubbing against the Condensor bottle and had frayed a few wires that went to the Coil plug connector. When the Condensor produced enough condensation the water would cause a "Short" and make the coil seem to fail.

I fixed the frayed wire, and wrapped a split heater hose between the harness wire and condensor bottle.

Also I am extremly carefull when I wash my engine so that I do not get water near the plug wells.

Also I remember an the 2k models the AC condensor lines run above the rear cylindrs, when enough condensation built up it would drip into the plug wells and casu the coil to short. I beleive this issue had either a TB or recall.

Good luck, but I do not think replacing the engine will do anything to fix the issue.

 

I know this is slightly off topic but anyone know if the 5.4 triton from the f150 is the same as the f250? And also how different is it from the expedition 5.4?

 

What year are you interested in.
In 2004 the 5.4 cam drives were changed in the F150/250. Other lines may or may not have got the change until later when the full cam changes were made as well as the 3 valve heads.
For all the vairations, the PCM programs were different.

 

I was hoping to make this reply tomorrow after another successful to work and back home run. Well, that's not the case.
Changed out all 8 coil packs yesterday after work, used the dielectric grease on the end of the boots. One of the original pack boots had fair sized cracks on the end. Took it for a short spin afterwards with no problems. Went to work, 30 miles, and back home, no problems. Left shortly after getting home to run errand, after 10-15 minutes of normal driving, it bucked!! Darn it!! After 3-5 minutes more of driving it did it again. Everything during the swap out seemed to go fine. Don't feel like I was too rough with any of the wiring. I think I will check out what kspeck posted, with the wiring. Oh, no CEL either. I will see how it does in the morning....don't really think it is just going to go away on its own...

Oh yeah, this morning as I was driving in, (didn't notice this when I drove directly after swap out), in overdrive, when I would let off of the accelerator after say 1 or 2 seconds the truck would feel like it was engine braking. The truck normally coasts when I let off accelerator in overdrive. No CEL. It did not do this on the way home or this afternoon when the buck came back.

I'm not sure, but lately I have been smelling a funny smell more than once but not all the time, and have just attributed it to some vehicle's exhaust in front of me that stinks. I'm not sure if it is a rotten egg smell, but it may be. I don't even know what the rotten eggs smell means....I have read something like that in some post in the past. Maybe I'm just starting to go crazy!!

Still trying to stay Ford Tough!

 

Here is the last thing to do.
You need to get a good Scanner with the ability to trap the fault live during drivng.
This will give the trouble area to look in.
These systems were not built without various ways to find an issue.
It's just that it become increasingly more complicated to do after the easy things are done.
It is still an ignition or DC power issue.
Bucking is the total loss of one or more cylinders by missfire, PCM processing stoppage or feed power interruption.
It could even be a PCM switch for one cylinder's coil.
Were hanging in here with you and not telling you an engine change will solve the issue by guessing like the other sources tried to do.
Good luck.