You mentioned the Evolution 46 on a Mustang PTS. Was that the RTF Version?

One of the problems with this model that the factory has not yet fixed is the cutout in the cowl for the engine. The cowl hits the low speed mixture limiter when you throttle up. This causes the low speed idle to be set to its full rich limit when you go to full throttle. You don't notice it the first time you throttle up, but the next time the engine sputters and may deadstick.

Solution: either cut the cowl to prevent the interference or remove the low speed mixture limiter. then you can get the engine properly tuned.

Brad