Problem with a 2002 3.8 V-6

[GodStang]

If you look at the a Dyno sheet for an engine it has more HP at higher RPM's. So when your car shifts to the next gear it goes to a lower RPM and there for it is making less HP resulting in a feel of loss power. If you put gears into your mustangs rear end it gets your car into higher RPM's faster therefore making that lag time shorter. It is normal all cars do that some more than others depending on how the car is set up. Hope this helps.