I looked around and didn't see any posts regarding this except possibly the TSB sticky.

I have a 2005 GT and it's been running rough when I accelerate WOT in third fourth and fifth gear (don't know about 1st and 2nd). The shop has replaced three coils with no real improvement. Personally I think it acts more like a fuel problem or lack of fuel for WOT at higher RPM's. The biggest problem is that I have my car in England so I have to wait for parts to get shipped every time they miss diagnose the problem (this ends up taking two weeks). The fault codes appear to point to bad coils but at this point I think coils can be ruled out. Has anybody else had similar problems? I would like to get this right the next time I go in. this shop is the same shop that almost every new mustang going into the UK gets processed through and they are professional but they lack experience with 2005 mustang problems.

 

:scratch:

First time I've heard of this one. Will be interesting to hear the result.

 

Sounds similar to the TSB sticky, maybe you need an upgraded ecu flash?

 

i think they upgraded the flash, but i'm not sure.