So if I'm going anywhere from about 35-50 and I step on it to pass, merge, or just quickly accelerate the truck downshifts. When it downshifts the motor stumbles very hard until it reaches a little over 4k rpm then it runs smooth and hard.

On Friday night I went to pass someone and the motor stumbled very hard. The check engine light started flashing and the motor ran like $h1t. I pulled over as soon as I could and killed the motor. I started it back up about a minute later and it ran fine.

I took it to my friend's shop and we hooked up a SnapOn MOBIS. It said there was a misfire on the #3 cylinder. Well I was down on the Chesapeake bay about 200 miles from home. I called the dealer on Saturday and made an appointment for Monday morning back home.

Well when I got there, the code was gone. I had driven over 300 miles so it fell out of memory. The service writer called and I told her what the driving conditions are when it happens. She said they couldn't duplicate it...funny as soon as I got in the truck I had no issue recreating the problem but couldn't get the code.

Grrr...guess I'll have to waste half a day at the dealer so I can drive a tech around since they're incapable of driving about 45mph and then flooring it.....

 

Any luck on getting it fixed yet?

I wonder if it has anything to do with this:
https://www.f150online.com/forums/sh...d.php?t=312997

 

Ford Just Issued A Letter On The 05,s With The 5.4 For Sticky Fuel Injectors And Raised To Warranty To Like 120k On Them Thats Prolly Your Problem