If it seems as though your aircraft is slowing down or bleeding excessive speed during taxiing, a possible cause could be intentional application of the brake pedals whilst steering. We suggest adding some nullzone to your braking axis, the real aircraft has a 14% 'nullzone' at the beginning of the pedal travel - we further suggest, depending on your hardware and personal preference, to make a somewhat exponential curve (so the brakes become more effective as you push the pedals more). We chose not to directly force the 14% nullzone into our simulation of the brake pedals, as this would lessen the total available travel on all hardware that can be used to modulate the brakes.
In a future release, the controls configuration page has a braking nullzone that will be set to 14% by default. If you have issues with your brake axis being too short for your hardware, you can modify this value to be less.