Hot Wheels Stunt Forumla Fuelers Question?

I'm trying to get this thing not to use stunts. Which is ironic because that's what it's intended for.

Anyway, I noticed that on test mode (or when the switch is on 1), the vehicle will have a short burst of speed, and then stop accelerating, but continue to move without flipping.

This only happens sometimes. Is there a way to enable this consistently in test mode? Or is there a modification or workaround to remove the stunting aspect of the car?

Help is appreciated, thanks!

NOTE: I did get the non-stunt function to work for about 5-6 tries before it reverts back to normal. But whenever I switch out the liquid it seems to reset.