Well,, than that would solve this problem of it running to lean and fix the problem all by it's self..

Where I had to replace 2 COPS on the driver's side to fix it..

Which brings up something I have been meaning to add to this thread.. On my 4.6 2002 one weak COP gave me just the misfire , where two of them gave me the Engine shutting down for a fraction of a second till it got so bad that it shut of the left bank completely once or killed the engine at 75 MPH once..

So far after replacing #5&7 COPS it's been running fine..

 

When the CEL flashes from a loss of ignition, it is "inferred" that fuel will pass out the cylinder and into the cats to burn.
The software designer put that little bitty in the control program as a logic for observation.
This is NOT a detected rsponse by the OX sensors.
The Ox sensors are well ahead of the cats just down stream of the manifold/head pipe connection.
They will see the unburnt Oxygen and 'could' richen up the injection to the 'next' cylinder in the fire order because the system normally controls fuel injection that fast for the next one in line to fire.
Good luck..

 

thanks pdqford , im thinking its the coil pack because not too long ago we replaced the plugs and wires and it started missing again within 10,000 miles, although it is throwing a cylinder #6 misfire code

 

You could swap the coil packs from side to side. Just be SURE you get the plug wires back in correctly. Then see if it throws a code for a different cylinder.
If the code is still #6, then swap #6 plug wire with another one of about the same length.
If it STILL throws a #6 code, then swap #6 plug with another plug.
If it STILL throws a #6 code, swap the #6 injector with another one.

 

thanks pdqford i will have to give that a shot

 

Hello!

First post. As indicated in the subject, I've experienced the same symptoms of the jerking/hesitation at slightly different speeds (35-45). Bluegrass seems to have helped many with this problem. Before I go and try the coil pack replacement, I am suffering from an additional problem: my idle is really rough. Doesn't stall, but comes pretty close unless I give it gas. Happens in all weather conditions and when the engine is hot or cold.

Would a rough idle be another indication of a bad coil pack? It SEEMS like it would be similar condition to low speed in overdrive, but there is no load so I don't know if its supports a coil pack issue or contradicts it.

I have been dealing with this for years without any success from dealerships to local mechanics. I've done things like MAF, plugs and wires, EGR valve BECAUSE of this issue. I'm hoping Bluegrass, or someone who has gone through this, will give me some indication that it all makes sense and the coil pack(s) should be replaced.

Thanks in advance.

 

I'm sure their first comment will be...
Are there any codes up?

 

parisilon,
First thing to do is look at the misfire monitors for all 6 cylinders to see if any cylinder has a high count.
If yes, address it with plug, wire, coil remedy etc.
And recheck to confirm after some drive cycles.
.
If the EGR is 'involved' (not the cause), disable it to see if the issue is affected. Remove the vacuum to it and plug the line. Force an EGR code so it's operation is suspended until you hook it back up again.
.
You have to find a base for any action before any possible repairs are attempted so you understand the source, or it just guessing.
.
A dealer has the ability to look at this live data or the use of a good scanner that can view mode 6, test 53- 1,2,3,4,5,6..
Since you enjoyed the problem for years, it's time to do it right.
Good luck.

 

Thanks for the reply. I've tried all different mechanics including dealerships. I have a small bit of timing chain noise when the motor is cold. Dealership told me I needed new timing chains and that was the cause of the problem. I seriously doubt that is the issue. Mechanics in this day don't seem to be able to diagnose what the problems are and just replace with a best guess.

I've also had the motor smoked to see if there were any leaks and also had a compression test done because I thought I was experiencing this o-ring intake manifold problem. No leaks though. So it seems like this electrical (coil pack) problem could actually seem/feel like a vacuum issue when in fact it is not.

I currently do have a CEL on now. I did have the scan done by my local mechanic and used a relative's scanner as well. Strange thing was when the truck was at idle, the scanner said something to the effect that the gas cap was not tight (or something like that). I've replaced the gas cap and, obviously, no change. When I drove with the scanner connected to the motor, I believe I was getting misfire codes on one of the cylinders. I'll have to borrow that scanner again and see if I get the same code. If I do, how can I test if this cylinder's coilpack is actually bad?

If I do what you say with the EGR value and I do not notice a difference, what does that tell me? The EGR is bad (even though it's new) or I am not having the coilpack issue? Basic questions, but clearly I do not have any intuition with this problem.

 

From your last reply, your going round and round in confusion with too many people involved and too many opinions and not getting anything solved.
Begin from scratch and address the misfire.
Use a Scanner that has a fault trap feature that will freeze data when it happens while driving, then you know which cylinder is the fault.
Address the code if not involving the cylinder misfire.
Codes and Scanners are to solve these issues along with knowledge of the systems. There is no other ways to do it except guessing and throwing parts at it.

The way your handling it is making the process more difficult than it needs to be.
As far as the timing chain noise, likely it's the chain tensioner/s guides that are worn, not the chains.
That requires taking the front cover off to get at them for replacement.
Often the cause of the wear is using oil to heavy in weight, being used over the long term. The tensions created at cold/cool starts become excessive as these are actuated from oil pressure.
Good luck.

 

Bluegrass, thanks for your wealth of knowledge! I was born in Paducah so you hit home with your screen name.

1999 F150 4.6L have the same "stuttering". I changed my plugs and wires with OEM Motorcraft and a few hunded miles later, stutter is back.

I will find someone with a scanner that has a fault trap. If I have a misfiring cylinder I will address it with plug, wire, coil remedy etc.

One question I do have for you though is, when running the wires back through the little clamps that hold the wires in place on the way to the coil packs, it is criticle to put the wires back in the exact spot? I may not have got them back in the exact spot.

 

They need to be put back in the same line up to help prevent crossfire.
Good luck.

 

My truck is a 2006 F150 5.4 L with 96000 miles. The same symptoms as described in previous posts. Jerking when you ease back into the throttle at about 45 mph. I was ready to take it to the dealership when I thought about looking it up on the Internet. I started searching and reading. Within about thirty minutes of searching I found this site, so after reading bluegrasses's responses I decided I would would purchase only one coil pack and change the pack of one cylinder and test drive it. If it didn't fix the problem I would take the old coil pack removed and use it to swap out with a coil pack from another cylinder. I ended up getting it on the first try. Looking at the engine from under the hood, I changed the left front cylinder first. I test drove the truck and all was good. The truck even accelerated better.

I just want to thank Bluegrass 7 for taking the time to educate us on this issue. You saved me several hundred dollars. Thank you again!

 

I had this problem about 30,000 miles ago. I replaced plugs and boots and solved the problem. Now I have the miss under light acceleration and also at idle. Of course it is intermittent for both but has gotten worse over time. No codes are showing. I plan on trying a code reader while driving. I would like to know if the miss at idle indicates a different problem than just a miss under light load. Thanks much for all the helpful info.

 

A reader won't do for the misfire.
You need a good scanner capable of being set up in a 'trap' mode to trigger on any fault and freeze the data for viewing.
Good luck