#09,
That's a new one on me
The double pumper is not all that different from a single pumper when it comes to how the thing squirts gas into the manifold.
The primary accelerator pump and the secondary accelerator pump (on a double pumper) only "pump" gas when the accelerator is moved from idle all the way through full throttle. The only way I can understand the relationship of bumpy roads and excessive gas is if your foot in jumping around on the accelerator with every bump....... not too likely I imagine.
- Jim -