Never a good idea to chase a problem with new parts regardless of when parts are estimated to wear out. I would not move forward based on assumptions. Troubleshoot, troubleshoot, troubleshoot. Find the core issue first. That's something Dads know from experience.

You mentioned that it starts with deceleration and only sometimes happens (starts) during acceleration. Do you mean it sometimes doesn't miss at all, that the missing is intermittent? Does it happen whether the engine is at operating temp or cold starts? Most of the most likely 'common' problems would be associated with acceleration when the engine is under most load so would like to learn more details about severity, conditions, and frequency.

Cleaning the MAF doesn't always work. However, if the MAF is bad the misfires would normally be all cylinders rather than just 3.

To troubleshoot for vacuum leak the best method is a smoke tester. IMO it is a must have tool for every DIYer. There are several videos on youTube showing how to make one for about $20.

If you want to find out if the problem is a coil, move one of the coils from a cylinder not showing a code to one that does, swap them. Clear the codes and see if same codes return or misfire moves to the other cylinder. You can verify if it is a spark plug in the same manner.

If you don't use a premium brand fuel that usually have cleaners in them do so for next fill up. Gas I use already has Techron in it. Otherwise, as mentioned, add a can of Techron to the next 1-2 tanks of gas.

__________________
X5 4.6 2002 Black Sap, Black interior. 2013 X5M Melbourne Red, Bamboo interior
Dallas