Howdy all,
I searched the threads before posting this and I am looking for some confirmation or ideas.

I have a 99 F-150 5.4 2wd with 257,810K miles on it.

I followed Bluegrass' recommendation in the transmission shuddering thread and changed out my plugs. The truck ran well for a while but over the last week has started the shuddering again. Before, this would only happen in the 45-65 mph range, now it is doing it intermittently at start up, idle, at varying speeds in wet or dry conditions.

No CEL, new motorcraft plugs, I checked the gap before placement and adjusted if needed, 2 new COP's (I understand even new ones can go bad). I have gone back over the coil packs and boots to check for loose wires there, or anywhere else in the engine. I have a new PCV, at the recommendation of the local dealer I removed Idler Air Controller (backside of intake) and cleaned the carbon out of it. He seemed to think that I might have a vacuum leak. I have a hard time believing that since the problem is intermittent, and there is no obvious hiss from a vacuum leak. Also, they (the dealer) didn't bother to put it on their scanner because it wasn't showing a CEL.

So, is it most likely a COP failure, or is there something else I should look for? When I go to work this evening I can run the truck by O'rielly's and see if their scanner will find something.

Thanks,
Craig

 

First, check engine vacuum at warmed up idle. With that many miles, 17-18" would be pretty good. If it shows 14-16", and wavering, start checking hoses and vacuum lines. ANYTHING connecting to the upper intake, valve covers, underside of the intake air duct work, vacuum line to the brake booster, etc.. If you have a hand operated vacuum pump, like a Mityvac, see if the EGR holds a vacuum, without any drop off.

If you have a multimeter, check the TPS. at idle, the signal wire should be about 1.0 volts, and increase as you manually open the throttle.

Aside from all this, it could be something as simple as corroded contacts on the crank sensor. Dirty or loose connections can give intermittent signals, but not do it long enough to trigger a code.

Dave

 

Cool, thanks for the reply.

Craig

 

Check engine light came on on the way to work. Codes P0107 and P0153. So a COP and an O2 sensor. COP will be replaced this afternoon, but how long can I go on a bad O2 sensor?

Craig

 

A cop ? PO107 is the Baro sensor (if my info is correct, about 40 pages, from Ford). It takes the place of a MAP sensor.

Dave

 

My bad P0307 Cylinder 7 misfire. I worked all night. Also, any opinions on who has the best prices on an O2 sensor? For the one in front of the CAT O'Reillys wanted 80.00. Off to Rock Auto.

Thanks for the input Dave.

Craig

 

I'm not sure if you still have the missfire between 45 and 60 but if yes, you still have a bad coil.
I have never made mention of it in past posts but a bad coil can cause the generation of other false codes.
Get the offending coil first then see if you still have other codes after clearing, to address or you will spend and get into confusion about what has/had happened..
If you don't, you may end up chaseing ghost codes.
Here is what I believe happens to cause them.
When the faulty coil dumps it magnetic charge, a signal may be reflected back on the PCM ground lead to the PCM.
The PCM still looks at the coil circuits for faults.
This can upset PCM processing of other functions and even stop processing for a moment making the truck feel like the ignition was fully interuppted, then return as the PCM resumes it's processing as if nothing had happened but may 'faulsely ' logic it detected a fault.
When this happens, the truck takes a near violent jerk then proceeds to run on.
I have researched this by working with it on my own truck until the faulty coil was removed.
I have seen other seemingly unrelated codes as well.
What this was all about is I installed a set of ACCEL coils about 4 years ago and one by one they all gave up so I had an oppertunity to see and work all these things through with only a code reader that did not tell the whole story..
Today I have a good scanner and can trap a fault while driving and see what had happened..

Good luck.

 

Thanks for chiming in Bluegrass. I had an extra COPS at the house, and replaced the bad #7 with my spare. About 15 minutes into my drive to work the truck started running rough again. Run rough for a while, smooth out, run rough for a while smooth out, etc......

Doesn't matter what speed, going up hill down hill, or a flat surface. I'll go back to O'reilly's again in the morning after work to see what the code reader says now. I am sure I have lost another COP, it is acting just like it did before. If it is another COP I guess I'll just bite the bullet and replace them all at once versus repeating this process.

Just frustrating doing this over and over.

Again, thanks for the input.

Craig

 

I ended up getting a new COP for the #7 plug. Local Ford house scanned the truck for me and confirmed the failure of that COP.

On a side note if it isn't violating forum rules............

Gloff Ford in Clifton Texas has been beyond helpful to me and my family. No charges for certain things, took a vehicle in for a brake job before a vacation and they informed me my brakes didn't need replacing at that time. They could have gotten me for a few hundred $$ and I would have never known the difference.

Craig

 

I assume the coil cleared your issue.
If so, as inferred in my last reply, ghost codes can be generated from bad coils under certain conditions, so disreguard them after clearing them out as old history.
Good luck.

 

Question for Bluegrass - Which scanner would you recommend? Noted on another thread someone was also asking about scanners and purchased a Altron CP 9580 from Amazon.

 

A mid grade scanner that is capabile of looking at alot of system operating parameters is the SEARS Craftsman 20890 made by Innova.
Runs about $180. At this level you cannot do any program commands but can do fault trapping and look at the PIDS.
It will also do the later CAN systems.
On other makes like Chrysler, it will look at nearly twice the amount of info in depth.
On Fords there is enough to work with to ID a fault by comparing the info with specs to see a pattern and any out of limit readings that exist, then doing further tests to pin point the fault and make the repairs.
An example of a parameter that can be seen is the "short term fuel trims" (STFT).
There are two, one for each bank. One out of limits as compaired to the other would be an indication of a fault in one bank's fueling. Of course if the trim is out of limits, a code is set that you can also see, to associate it.
Good luck.

 

Thanks for the info Bluegrass!