Having high fuel consumption on my Toyota Carina e 1994 model. Please what may be the causes?
Well, as per the comments, there are many possible reasons for a change in fuel consumption.
I would suggest establishing a baseline by doing a thorough service : air filter, fuel filter, sparkplugs checked or replaced etc to make sure of the simple things. Also tire pressures, checking the brakes are functioning correctly ie not dragging or binding. Have the codes read if that system exists.
Once all of this has been done, evaluate the fuel consumption accurately - I use the « brim to brim » method as trying to base fuel consumption on 1/4 tank is not very accurate - then see how the fuel consumption compares over 2 or 3 tanks of fuel.
Hopefully it should be normal, unless your use is the cause - high loads, lots of stop / start etc.