I activate the speed brake and after I'm on the runway, I push "R " on my keyboard, the key I designated in FSX to activate the reverse thrusters under the command " decrease throttle quickly ". After I do a replay I notice the speed brake panels on top of the wing are activated before I'm on the runway. Also, The engines are open before I'm on the runway. I hear the reverse thrusters the second I push " R " and they are working, but the image is wrong.

I suggest you post in the PMDG forums.

 

I activate the speed brake and after I'm on the runway, I push "R " on my keyboard, the key I designated in FSX to activate the reverse thrusters under the command " decrease throttle quickly ". After I do a replay I notice the speed brake panels on top of the wing are activated before I'm on the runway. Also, The engines are open before I'm on the runway. I hear the reverse thrusters the second I push " R " and they are working, but the image is wrong.

Do you have R on repeat? If the reversers get stowed when you depress R, that would disable the autobrake.

That's porbably because of the, frankly, quite syupid replay function in FSX. If you want decent replays, get FSRecorder or something like it.

It's definitely a problem with the FSX native replay function. It gets out of synchronization on playback - especially with complex add-ons with a lot of animations. Kind of like watching some YouTube videos over a slow internet connection, where people are speaking, and the audio of their words gets out of sync with their lip movements!