It's an easy solution, the throttle plates scratches inside the throttle body because it's dirty of carbon and the scratch you hear is friction. The friction delayes the pedal response. If it's not dirty, it's something related to the maf sensor that doesn't calculate the amount of air correctly. Can be dirty too. Something as easy as a new filter will prevent to happen again for another 2 years.I own a 2014 Mazda 2 sport manuel trans, 90,000 on the odometer. Recently noticed a slight scratching noise & slight delay from the engine when I press gas pedal in neutral for about 1 second before it actually starts revving. Also, I noticed its getting a little sluggish when accelerating not sure if the 2 are hand in hand issues. Never had a check engine light (knock on wood), no issues and general maintenance has been kept up, any information would help thanks!