High fuel consumption Mazda Allegro (protect-Artis)

Help with difficult problem mazda 323 model 1999 displacement 1.6 (allegro version Latin America Colombia)Hello, good afternoon, I introduce myself, my name is Jesus David Ramos Vernaza, I live in Cali Colombia, I have seen several of your videos on YouTube and I would like to know if it is possible and you can help me with a fault that they have not been able to find in my vehicle, which It is a 1600cc mazda allegro model 99, with OBD1 port, the vehicle currently has an excessive fuel consumption of about 28 kilometers per gallon without using the air conditioning, if I use the air conditioning the consumption increases to 22 kilometers per gallon, which It is a really absurd thing with fuel being so expensive here in Colombia, the vehicle's tank holds 10 gallons with the cluster needle on the first line, that is to say that with those 10 gallons of gasoline I travel on average 280 kilometers, which gives me He is puzzled, they have measured the vehicle's engine compression, they have checked the oxygen sensor, I even had it imported directly from the US, the Denso brand, the original one, which is a single wire, they have checked the Maf sensors, TPS sensor, ECT sensor, apparently All the parameters of these sensors are within normal parameters, they have measured fuel pump pressure, returning the value within specification, I even have a launch crp239 scanner with which I manage to scan the vehicle but it does not show any fault code, I would appreciate if you can guide me on what else to check since that fuel consumption drives me crazy, the vehicle, as I understand it, should travel on average 38-40 kilometers for each gallon of fuel.

Thanks

Jesus David