short dropout at 2500

SX4 1.4 140 hp (no hybrid) Hi, I usually have a short dropout at 2500 when accelerating moderately, as if the engine “swallows” itself. So e.g. at the intersection at 1500 rpm give half-gas, at 2500 then the swallower comes, then it goes again normally up to high speeds, if you wanted. Do you have that too? Is this possible normal, or not? The consumption is also relatively variable, from 6 to over 8L, despite regular, even commuter drives, each Who knows?