Subaru legacy ej20 loss of power at low rpm

Hello,

I have subaru legacy 2000 92kw petrol/gas,  my car has automatic transmission,  while accelerating car struggling till 2200rpm then the power is back on. Spark coil, spark plugs, wires everything was changed, maf, map all sensor replaced, new knock sensor, catalytic removed, o2 sensor replaced, valves adjusted, the same situation while driving with lpg, so its not the injectors. Every single sensor is replaced/cleaned and checked as good. No check engine light, no codes