I have to rev my rps up really high to get the car to go in motion with a jolt! on 2005 Mercury Grand Marquis

When it does go in gear it rides smooth till I stop and accelerate again. My code was for throttle actuator? But feels like trans?

Check trans fluid level and condition , then have scanner with live data to properly diagnose the 'throttle body' code. Code indicates circuit NOT just part.