Have a 2011 FL2 with 44k miles. Recently developed a fault where the throttle response seems to be variable. No warning lights or messages. I am guessing that its a throttle position sensor issue. Any other suggestions before I take it in (it's under LR warranty)? Is this a common fault?

Please explain what do you mean by throttle response to be variable...
When, how, conditions,....

sometimes the engine surges, sometimes there is a loss of power on pulling away and it's as if the throttle has become less responsive then it returns to normal