Im flustered i need some help. I read through as much of this as i could but my problem persists.
2011 Ecoboost, ca 91 octane truck. 38,xxx miles, have had livernios v2 tune for 90% of those miles. Always ran flawless. Recently as the weather cooled i noticed a slight "flutter" at WOT sometimes. I thought it could be the plug gap, so found you guys and Rick a Livernois recommend a .030 gap instead of the factory .034-.037 range. Stock plugs were all over the place. .037/.038/.039. etc
re-gapped and it idles and drives through neighborhood fine..... untill i build boost or accelerate up to 25-3000 rpm's. it misses and shakes violently!!
Bought new OEM plugs from Ford.
Motorcraft SP-528 CYFS-12-Y3 was what i was given. slightly closed the gaps trying not to hurt the electrode when measuring. Used flat feeler gauges this time rather than the cheapo coin looking $1.99 gap tool. Same problem!!!No matter running V2 or stock tune!
Everything is plugged in and i TQed the plugs to 20 lbs as the plugs recommended (18-25.3lbs range)

No CEL, the very first time i plugged in tuner it found a DTC code. #P0305 - cyl 5 misfire. The dtc has not returned since.

any advice??? what am i doing wrong?? Is the truck in a limp mode for a set milage even though there is no cel??
Ill regap to factory specs now as i hope to wait for replys!

edit: The only plugs i remember unplugging since the first time are the driver side valve vent hose, driverside high psi fuel pump(above last cyl), and the 6 injector pack clips. Did i loose one i dont remember??

 

Move all the plugs over a cylinder and see if the misfire code moves with it. Sounds to me like a bad plug maybe. I haven't done this yet on my truck because I'm pretty sure the mechanic is going to under the shutter tsb.

 

Not a bad idea, but the misfire code was for the old plugs these are the new ones. So far the misfire wont duplicate, but then again i havent gone further than around the block a few times

 

Ahh yes. Does sound like a bad plug to me. I've heard a lot of horror stories of people cracking them, not sure how though lol

 

I would take it to the dealer and see what they find. I would say bad coil.

 

Leadsled, I think you probably cracked one. You torqued too high. The spec is 133 inch lbs, 11 ft lbs. That's is seriously not tight as all. Get a inch lbs torque wrench, most ft lbs wrenches that is was at the bottom of the scale and will be inaccurate. Seriously, 11 ft lbs is so low you could do more with a 1/4 inch ratchet. Triple check the torque when you do it.

 

Where does this 11 ft lbs come from!? I just installed oem plugs and torqued them to 24, per what is written on the box!

 

Went on NGK website, states 7.2-14.5 for 14mm conical head in aluminum. I guess that's where the 11 comes from. Should I panic?

 

Hopefully just a cracked plug. I'm not sure what the damage to the head would be at 24.
Might have been a good idea to read the first page of this thread first. ;-)
Good luck

 

Seriously, oem plugs box states up to 25. I am beyond pissed.