Bluegrass7, I know I dont have the same problem as the the other guy, but Im new to this forum and im still trying to figure it out. as for the truck, I changed the shift solenoid because it will shift from 1st into 2nd, but not 2nd into 3rd.. I stated the 3000 rpm cuz that's what took notice of when it bucks at 35mph... its something in the tranny cuz in park I can red-line it and it wont miss a beat... but under load condition it will buck...

 

My tech hooked up his $11k scanner to my truck & we went for a several miles drive on the highway. The condition happened many times but no misfire was detected & everything was normal. Any suggestions on what we should try next? Thanks.

 

Good your Tech gave you some time but how was he looking at it?
Did he set up a trap?
Has he looked at mode 6 test 53 at the misfire monitors?
What i'm trying to say is your trouble has to be looked for and not just depend on a simple Scanner response looking for a code without some additional effort, or you will never get hold of the issue.
The shift solenoids are eclectically monitored by the computer at all times and if any go faulty a code would be set.
There can still be a mechanical transmission issue aside fro the solenoids the computer cannot see.
I'm sorry to be hounding you but you came for help so I try give you more info than your getting elsewhere, trying to help you.
Good luck.

 

You're not hounding at all. I want all the input I can get.
He sat in the passenger seat with this hugely expensive Snap-On brand scanner/computer plugged into to the diag. port. sitting on his lap. He did that test & watched alot of live data on it's large screen while I drove. All normal readings including the O2 sensors which I happened to ask him about. I properly should have mentioned sooner that this condition seems to still be there when I shift into neutral at highway speeds. He found that interesting & figured the tires needed to be balanced.
He did that but it actually made things abit worse. My steering wheel now shakes which of course means a front tire is out of balance. He uses a bubble balancer & puts the weights only on the inside of the rim so they don't show. He says that he gets good results with it. He's also a friend so I do trust him.
I had my sister drive my truck on the highway while I drove along side in her car. The only thing wrong I noticed was the R/F tire bouncing a little which would be the reason for the steering wheel shake. I think my tires hate his bubble balancer.

I'm thinking that we're barking up the wrong tree. Perhaps it's something like a weight having fallen off the drive shaft causing it to be out of balance sort of thing.

Maybe its worth mentioning that I had him replace all 4 shocks a couple weeks ago and a couple days ago a clunk started happening in the front end which I can feel thru the steering wheel. He checked it out while balancing the tires & said it was caused by a worn left front upper control arm bushing & that the arm would need to be replaced. I'm looking for suggestions on where to buy one.

I hope all that additional info helps. Not sure what else to mention.

 

I'm thinking that the way I wrote the cost of his scanner($11k) may have been confusing. I was trying to say it cost $11,000. Hard to believe...I know. But true. And he does know how to use it as well. Just wanted to clarify.

 

Bluegrass has you guys on the right track. What happened to my truck sounds eerily similar. Truck was running perfectly fine, head gasket let go, repaired by two ex-Ford techs, and shudder started. Truck would shudder/jerk at anywhere from 35 mph on up, anytime you accelerated. I was getting intermittent mis-fires from 4 of the eight. They swapped them around, but still got it on 2. I had no idea how old the cop's were, but I know 6 of the eight were junkyard cop's purchased by me. I found a supplier who SWORE his cop's were "copper wound", not aluminum like many of the cheaper ones, and bought and installed his. 5 months in, and no problems.

I would highly recommend the Motorcraft COPs if you depend on your truck for work. I went with the off brand because it is my son's ride, and if it craps out, he knows how to walk home.

Bluegrass sounds like a TRUE mechanic who looks to fix the problem, and not throw parts at it. Trust what he is telling you. Bluegrass is helping you save money by only purchasing the COPs that need replacing. For me, the truck being 16 yrs old, and no idea of the COPs past history, I just replaced them all.

P.S. The ONLY way to know if the COPs you purchase are copper or aluminum, is to cut them open. Of the 2 known bad Motorcrafts I cut open, BOTH were copper wound.

 

Here is another way to look at some of this.
An $11k Scanner with ALL the programs and cables for making a living with, testing PCM, and all body systems plus able to send commands to the systems and see the results,may well cost a lot of money.
The mfger has a 'name', has to build quality, has to pay for access to all the software and pay for assembly to do all this at that level.
In the O.P. case this level of performance is not needed.
A $200 Scanner will do.
Please don't hang you hat on the cost of a Scanner as an excuse to defend.
You still have not identified the problem even with an $11k Scanner system.
To repeat; has the misfire monitors been looked at?
A misfire is not an Ox sensor, a fuel filter, an IAC, a TPS, a CHT or any of these type sensors.
It is the absence of spark or fuel (at time of combustion).
It can be a crank sensor plugup, PCM relay contacts, fuse/relay not fully seated as a cause of the instant losses.
Certain drive line problems can feel like a misfire but you can differentiate between them.
I may seem a bit defensive, but until the source is being pinned down, please do not try to defend an $11k Scanner and a friend because you don't know and I don't know [here] his ability to use it or how it was used.
If this is rejected, then an $11k scanner cannot find the issue, might as well take the truck to the junk AND throw the $11k Scanner there with it.
You have to check to see either it is the control system, or the drive line/ suspension to even get to first base.
************************************************** *********
Misfire in OD at light throttle is a faulty coil.
This occurs under very specific conditions.
1. The EGR is opened.
2. The air-fuel ratio goes lean over 20 to 1. Fuel is reduced and ignition timing is advanced.
3. Ignition requires all the voltage a coil was designed to deliver under these conditions +.
4. If any coil has lowered output 'not necessarily a (total) failure', a misfire will occur, you will feel it.
This will be registered in the offending cylinder's software monitor.
In addition, eroded spark plug gaps will add to this.
In a marginal situation, replacing plugs only sometimes appears to clear the misfire by slightly reducing the voltage required to fire reliably, only to return again in less than a thousand miles after the plug in the offending cylinder has begun to lose it's sharp edges.
Another hint is the ignition timing retards at the time of misfire. This can be seen on the Scanner.

I can't be convinced differently because I have been their and done it and saw it before.
Changed plugs, measured/cut coils apart, looked at monitors, studied the system to put it all together to be able to get to this point.
The reason is, when I came here to these boards I saw a lot of this with no positive answer until I had the issue, done the research work and found the proofs and causes
.
Here is another mind blower for some. Autolite plugs of the correct heat range work just as well as Motorcraft. I just changed mine at over 175,000 because I was in there doing other work. You could drive a Tank through the gaps they were that eroded but still working with a good set of coils and no misfires registered in the monitors on my $180 Scanner used for all this research work..
Good luck.

 

Thanks for all that, F150Dad & Bluegrass. I'll be running the info by my tech.

Am I correct with thinking that if it is a misfire, I would no longer notice it when in neutral at highway speed?

 

At idle and higher speeds that likely will be the case because the conditions that bring about the misfire are not present.
Here is why; the air/ fuel ratios are more normal near 14 to 1 not 20 or more to 1 and do not require the higher voltage to fire the charge.
High speeds does not fully equate to higher voltage needs.
Idle requires very little spark to keep the motor running.
. Additionally, EGR is called to operate only when two major parameter are present and for a timed interval.
They are road speed above about 45 to 60 mph and low TPS signal (light throttle) steady for a timed period then the computer calls for the EGR to come online.
When this happens things change radically.
If there is a coil failure it will be felt as misfire and registered in that cylinder's monitor.
The system never misses any of this unless some one has rebooted the computer and wiped out the data.
Good luck.

 

Thanks again, Bluegrass. I really like learning & knowing all kinds of spec's like that.

Here's the thing though, when in neutral I still feel the jerkiness of the ride that I was thinking was a result of the engine spuddering/misfiring.

 

Bluegrass - Do you happen to be familiar with a ScanGauge II?
ScanGaugeII : Linear Logic - Home of the ScanGauge
Check out the info about the built-in digital gauges.
It's a really neat gadget. I have one & find it very interesting to see the data change while driving. Such as ECT,O2 Sensor, Ignition Timing, A/F Ratio, EGR, TPS, BAR, Trans Fluid Temp, etc....
Although I don't know how to interpret all the readings, most I do & am very intrigued by it. With the info you've provided, I'll be paying attention to the A/F Ratio & Ignition Timing to see what those readings are while the condition is occurring.

 

My tech says he did a contribution test which according to him is the same as looking at the misfire monitors.

Since we're unable to know which cylinder has an issue, I'm considering having him replace the plugs. Since my truck is 16 y.o. with 81k miles, it's due & can't hurt. Would you agree?

He said I'll notice a difference using high octane gas instead of the low I have always used. I'm not so sure about that. Your thoughts?

 

tell your tech if he has a power balance feature on his scan tool to use that. go drive the truck while watch this. the coil that is weak will drop out when you are driving. don't hammer down on the throttle when driving, just accelerate steadily.

 

Thanks, Dr.Dirt. I'll do that.

If I have him replace the plugs, I'm thinking that I should replace the coils also. Aftermarket ones were recommended to me. What are thoughts on them?

 

Positively absolutely not. Higher octane fuel will not improve anything.
Higher octane provides no more power or BTU content, or clears any issue in a trouble free engine.
What does higher octane do?
It delays combustion 'flame speed' for use in higher compression motors that need it to control pre ignition and spark knock.
Higher octane in a 4.6 or 5.4 results in the PCM changing the timing a small degree to account for the difference in slowed combustion speeds and formulations. The end result is no gain worth the added cost..
Good luck.