Cylinder 8 misfire engine light

[BRAPPPP]

All 8 spark plugs wires are the same, it doesn't matter.

But that is the wire that Ford just replaced so wouldn't it make more sense to swap the wire that goes from the computer to the coil pack?

 

[MTF]

You stated they replaced the coil pack and the spark plugs, you did not mention they replaced the one spark plug wire from the coil pack to the outside spark plug.

 

[BRAPPPP]

You stated they replaced the coil pack and the spark plugs, you did not mention they replaced the one spark plug wire from the coil pack to the outside spark plug.

Post #7 I stated that. Maybe I didn't use correct terminology.

 

[MTF]

No problem, without doing a continuity test on each wire from the PCM to the coil pack, this going to be hard to diagnose.

---------- Post added at 12:08 PM ---------- Previous post was at 12:06 PM ----------

Is the dealer charging you an arm and leg to get this fixed?

 

[BRAPPPP]

No problem, without doing a continuity test on each wire from the PCM to the coil pack, this going to be hard to diagnose.

---------- Post added at 12:08 PM ---------- Previous post was at 12:06 PM ----------

Is the dealer charging you an arm and leg to get this fixed?

Yes I'm already $1000 deep that's why I'm on here looking for help to minimize costs.

 

[MTF]

Yeah, I feel your pain.

On Ford Parts website, there is a Pro section that has the whole OBD11 Diagnostic's Manual for your truck. You have to sign in to get to it though, but reading through it you may find something were missing.

---------- Post added at 12:48 PM ---------- Previous post was at 12:24 PM ----------

Just another thought, your battery is ok? Ground cables on the starter are ok?
Weak battery can do strange things to these trucks.
You should not have anything lower than 12.7 volts not running.
And around 14 volts running with lights and accessories on.
What is the volt reading on your hand held tuner or OBD11 scanner?

 

[BRAPPPP]

Yeah, I feel your pain.

On Ford Parts website, there is a Pro section that has the whole OBD11 Diagnostic's Manual for your truck. You have to sign in to get to it though, but reading through it you may find something were missing.

---------- Post added at 12:48 PM ---------- Previous post was at 12:24 PM ----------

Just another thought, your battery is ok? Ground cables on the starter are ok?
Weak battery can do strange things to these trucks.
You should not have anything lower than 12.7 volts not running.
And around 14 volts running with lights and accessories on.
What is the volt reading on your hand held tuner or OBD11 scanner?

Ill look those over but man i highly doubt the battery is an issue....
I am using the X3 scanner and was told that their can be issues with the X3 communicating properly to these trucks.
Possibly thinking about buying an X4 to see if that fixes the issue.....

Spark Plug (check)
coil pack (check)
wire from coil pack to plug (check)
plug from pcm to coil (looks ok but not replaced)
Injector (highly unlikely from multiple sources, plus doesnt seem like injector issue)
Compression Test from Ford Tech (check 3% error)

Also as i stated it only misfires under load...

I have had issues with the X3 scanner beforee.. It is odd that it would only be affecting 1 cylinder, but i guess its not impossible. Otherwise their could be PCM damage?

 

[whoisbigman]

As stated earlier, move injector 8 to 6 and clear codes. switch coil packs and wires. Injectors can fail. Wires can look good and be bad. switch everything from 8 to 6, clear codes, and see what happens.

 

[MTF]

I threw the battery thing out there, it's a long shot at best, but you have to cover everything.

I honestly don't think the X3 and the file written for it would do something like that.
While support has ended for the X3, as long as the file you have is written for it you should be good.
If you do go for an X4, I would ask your Tuner if you would need an updated Tune for it, just to be safe.

The X4 on the other hand has been getting updates about every month and a half.
I have sent an email Monday asking what effect the updates have on the Tune, still waiting for a response.
I'll have to shoot an email to Whipple I guess.

 

[BRAPPPP]

Also I learned today that when I run the truck it has to been ran hard for like 5 min before it starts misfiring and flashing engine light. Then once I go back to cruise or idle engine light goes away and no misfire. Strange. I do think the next step is injector swap but I have to take intake, throttle body, and 45 degree elbow off which is a pain in the ass to do.