[Walt Fricke]

Crash
How about changing the graph so RPM instead of speed is shown? I think that is more useful, and the software allows making that change from the data stored from the run.

Looks like a 3d gear run?

The ends of these runs look like either a rev limiter kicked in, or you took your foot off the throttle, not that the engine just wouldn't rev any higher. What was the deal there?

What fuel did you use? If detonation is a suspect, running some 116 octane fuel ought to help see if this is happening, or if it is some mismatch in intake/exhaust resonances.