It sounds like you aren't getting enough fuel, just off idle as the carb shifts from the idle to main circuits. I can't remember much about the Weber DGV's, but if there is a pump jet like the DCOE's/sidedraft carbs, you should increase the size of that jet. That's basically the jet fuel squirts out of, through the accelerator pump when you push the gas down with the engine off. It just bascially needs a bigger shot of fuel when you push the gas pedal. Maybe the DGV's you have to adjust this differently, but in DCOE's/Dellorto's, and even double pumper Holley's it's just a small replaceable squirter on top the carb.