Hi,
I have a 2002 Honda Civic ex (non vtec). It is consuming an excessive amount of fuel, about 8MPG (in the city) even though the traffic is light

Since I have only had it for a month and it is not like the previous owner had it, I did the following:

change filters (engine, oil and cabin).
oil change,
PCV valve change
IAC valve change (idle speed was unstable)
brake check
Today I realized when removing the oxygen sensor that there is no catalytic converter inside, I know this can increase consumption but I don't think it will increase by that much.

There is no engine light on or errors (it came to light P0420 low catalyst efficiency) but I deleted it and it has not come back.

Some of my OBD2 values ​​are, at idle after driving for about 20 minutes.

ignition timing advance for cylinder #1 (varies between -2 to -7.7 degrees)

intake manifold absolute pressure 41 to 45 kPa

engine rpm = 720 rpm
calculated load value = 41%
coolant temperature 90 degrees celcius
oxygen sensor 1 (varies between 210V to 780V rapidly)
oxygen sensor 2 (varies between 0.075 to 0.465 a little slower than sensor 1)

short range fuel regulation (-0.8% to 0.8%) in driving is usually between (-2% to 4%) normally is a little more time in a positive value

long range regulator is almost all the time at -0.8