I had an engine go bad on my 4Tec Nitro and recently replaced it. I also replaced the plastic gears (some teeth were broken) and the clutch shoes (spring was broken and shoes worn).
I replaced the gears with the exact same parts.

The last Traxxas App telemetry run I did was in June and the max speed was about 70 mph.

In the same parking lot I made a telemetry run with the Traxxas App today and max speed was only about 50 mph

I think I accidentally changed the shift point. Maybe something else?

I don't know how to attach files to this post. So Here are graphs of the RPM and Speed from the June run

Today's RPM and Speed

Any help in getting back to better speed is greatly appreciated