I have a "new to me" 2001 F250 Super Cuty Crew with the 5.4 2V. Ran great during test drives, 152K miles and the night I bought it I noticed the shudder just after the shift into OD on the way home. This concerned me, but not nearly as much as when the motor spit out the #6 plug the next day as I was driving from work to lunch.

I drove my steam engine sounding rig home that evening after work (slow and easy, with the injector disconnected to #6) and used the OEM brand 14mm insert kit (used the long one as recommend here), a new plug, and a o'Riellys COP. Truck ran like a raped ape for 6,000 miles, and then one a very cold morning at startup I got a misfire. 20 degrees F, had been for the past month.

I pulled pending codes to find a misfire on #6, so I pulled the plug and the electrode was almost completely gone, replaced the plug and COP, and the misfire was still present.
Over the past 2 weeks I have swapped COP's with #5 and 6, still misfiring and throwing the pending code for #6.

My question is, what the heck could it be? I have the shudder in 3rd and OD at the mild throttle settings, no other pending codes (also cleaned MAP/replaced AF & FF (no service history). There are no vacuum leaks, truck "runs" fine but for the misfire, back in the old days I would say it sounds like it was "loading up" when it is cold, but when warm runs better, still has misfire at idle and low/slow driving. No wicked unburned fuel smell, no flashing CEL, no rotten eggs, no bogging nor trying to die in any way.

I think a little more info would be relevant. The misfire is worse when cold, but nearly goes away when the engine is running at temp. When fully warmed up and idling there is an occasional but regular surge from an indicated (the dash tach seems to read a few hundred RPM over what scan tool reads) 850ish RPM to about 1000 RPM, smooth transition up and back down, like if one were sitting in a drive thru line for a few minutes it will cycle every 15ish seconds or so.

As stated, cold engine is worse, at highway speeds no issue. The lug or stutter is present at ~35-38 mph in 3rd (OD off) and same RPM range in OD (~42MPH) but not as bad in OD as it is driving around town in a 35 mph zone in 3rd/Drive.

Any ideas?? #6 Injector going **** up on me? Multiple issues?
Help Mr. Wizard!!!

Thanks in advance for any ideas!

 

Can you be specific , what brand insert and spark plug you used on #6 .

 

Did you take a compression reading on #6 yet?

 

Wolfboro, I used the OEM insert kit with the tap, seating tool, and 3 inserts, of which I used the longest one as recommended here. I also used a Motorcraft Platinum plug, oem style/model, at work so I don't have box handy.

Alloro- I have not. Basically the truck went from being parked in the driveway after work running excellent to startup the next AM with the misfire, the "new" (6k miles) plug electrode was burnt mostly off.
Replaced COP and plug, then with no joy from that swapped COP between 5 and 6 and miss stayed on 6. Changed plug again in case I "oopsed" something with the first.

 

ICDGary,

I am a bit confused , because I never heard of "OEM kit " . I heard of Timesert kit, I heard of CalVan and FullTorque kits , Helicoil and Dorman kits . So , you got me .

Also your spark plug should be " Motocraft SP479 " .

 

I don't know if the link will come through, but I bought it at AutoZone or O'reilly's, if you google 14mm OEM brand thread repair kit you'll see this:
OEM M14 - 1.25 Fix-A-Thread spark plug thread repair system 25647 - Read 2 Reviews on OEM #25647

And yes, the Motorcraft SP479 is it-

 

I asked because of the burnt electrode you described. When something like that happens you have to consider that there might now be a hole in the top of the piston, or a large scratch in the cylinder wall.

 

Makes perfect sense to me, I'll add that to the troubleshooting "to do" list, thank you

 

ICDGary says " The misfire is worse when cold, but nearly goes away when the engine is running at temp. "

It could be a sign for dirty "Idle Air Control Valve" .

 

Wolfboro, perhaps I am mistaken, but does the 2001 with the 2v 5.4 have an IAC? I thought not.

Edit-

Go figure, but I have a misfire on #6 cylinder, no low Idle issues, no other codes, no radical surging. I'll take a look over the weekend either way, but I don't think the feedback the engine offers points in that direction. I appreciate the suggestion for sure though!

 

My 2003 V-10 has it . According to O'Reilly website, they also have IAC for 2001 F-250 w/ 5.4L engine . Check out a "cleaning procedure " (on-line / youtube ) .
At V-10 , the location is behind the throttle (between throttle and firewall).

Is your second spark plug at #6 working OK ( no electrode wear ?)

 

New plug looks proper, given that its just 2 weeks old. Appears to be fine. Not wet, not burnt, a nice mid-gray.

 

ICDGary,
Just curious, how do you know it is misfire at #6 ? Do you have an OBDII compliant truck ? what kind of code reader you are using ?

 

great question, innova scanner, pending code is for #6 misfire, no other codes or pending. I suppose it could be another but then.. hmmm, now I wish it weren't storming out at the moment, I'd pull injector wires again to see if it's migrated.