Not yet it doesn't. The amount is too small!

Remember, iba't iba ang pagme-measure ng gas boys at auto-cut-off ng pumps sa full tank. Measure from a full tank and wait till it's at least HALF empty before measuring. This gives a better indication of effect and effectively reduces the percentage of error at the pump to around 1%.

Do this for two full tanks at least, and then remove the device, and do two more full tanks afterwards for comparison (same driving situation). Would like to know your results. :D