intermittent shuddering, no power and cel on problem

[jimmyducati]

Ive put about 3k miles on my 2010 SHO, 2500 of which it has been running the 4+ LMS tune. In the last week it has developed a bit of a problem.. 3 times in the last 200 miles while driving down the highway it will lose all power and the cel light will flash. At this time if you give it any throttle, something kinda hard to describe happens... It almost feels like Im running over a bunch of rumble strips and the engine hitting the rev limiter all at once (although the tach is not moving so the engine is not revving. Each time it happens i just coast until the cel goes out and then all is well again. I just checked to see if there are any codes stored and there are not.. I have no clue what could be going wrong, maybe something with the tune or if its a piece of hardware malfunctioning...

[DJE624]

That is scary.  The first thing I would do is go back to stock, run it a little, disconnect the battery for a few minutes, run it a little more then reload tune.  Make sure everything is off.  A/C, etc.  After you shut it down, open and close the door to be sure accessories/lights are off. Then load.

[jimmyducati]

Its VERY SCARY,, especially when you are trying to pass a semi truck when it happens. Im going to reload the stock tune today and keep in in for the next week or so, then take it into the dealer for them to investigate. Also need them to look at a "clunk" in the front right suspension when I hit a bump.. drives solid just sounds like a 100k mile car on a bumpy road.

[mjhpadi]

I would also check the knock sensor wires that are by the air filter to make sure they are not chaffed and causing a problem...it was fairly common problem on the 2010's and Ford has never acknowledged the problem, but it does exist, the wires rub on the sharp edge of the cylinder head and wear through the insulation to bare wire.

[SHOdded]

Ditto on the knock sensor wires.

[jimmyducati]

Ill check the knock sensors in the morning, that actually sounds like it would absolutely cause that problem.. like timing is being pulled when the throttle is pressed. Right now Im to busy staring at the new TSW wheels

[EcoBrick Bob]

I think you may have a bad spark plug... I have had this happen, but it's been a while. 
Have you changed them?  If not, you want to be running the 2011 and up plugs as the 2010 was different and Ford changes them as needed if they see issues...

[jimmyducati]

How could a bad plug cause this problem? I would think it would be constant, not once every couple hundred miles for 10-15 seconds...

[EcoBrick Bob]

I have gotten intermittent check engine lights, and finally a CEL when I have been coasting down long descents, like going into Chattanooga from GA on I-75.  CEL was "random mis-fire".  This was with the Stock Tune.  Tranny was using engine to "brake" car and that's when the misfire happened.. 

I have also had plugs mis-fire intermittently, which turned out to be broken plugs that only misfired at high RPM... Can't explain any of this as to why or why not the CEL's occur when they do... But they do.

[SHOdded]

Good to know the exceptions to the rule, EBB.  Valuable info!

[jimmyducati]

So Ill go ahead and replace the plugs, is there a recomended plug when running the 4+ and eventually a meth kit with a stage 5 tune from LMS?