acceleration hesitation yet RPM's respond

I have a question that might help (I hope). Since this is a drive-by-wire setup, is it possible that the PCM is telling the throttle to open AND advancing the spark timing? If so, then the tach would respond by deflecting upward even if the engine is mechanically not responding.

I know this is a stretch, but I'm looking for a way to explain the evidence thus far presented in a way that can be logically understood.

(Again, I don't understand the entire operation. I'm just offering ideas.)

Starship said:

Fake tachometer? That's too spooky. I actually have a Tiny-Tach for small engines (don't laugh). I wonder what I'd see if I were to hook it up. Anyway, the transaxle was what popped to my mind based on the age and mileage of the vehicle but who knows?

Click to expand...

Since our engines have COP (coil-on-plug), how does the Tiny-Tach pick up the signal?