Q for those that have driven the car for a while now with Synchro Rev

zilent_jay

It's mostly likely due to the feature holding the RPM...

For example:

When you manually rev match a downshift, you actually start letting the clutch out before you hit your target RPM. You also only blip the throttle so you are already off the throttle when it's time to let out the clutch, which means the injectors are already closed. This system doesn't know when you're going to let the clutch out so it's having to start the revmatch and prepare to hold the RPM by constantly supplying fuel until it detects you're releasing the clutch. That extra bit of fuel is most likely what you're noticing.