the open loop control regions similarly l ko2 represents an air fuel ratio correction coefficient which is calculated in response to the oxygen concentration in exhaust gases sensed by the o2 sensors 16l and 17 kls represents a mixture leaning coefficient which is set to a predetermined value smaller than 1 0 when the engine 1 is in a predetermined decelerating condition while it is set to 1 0 when the engine is in a condition other than the predetermined decelerating condition k1 and k2 represent other correction coefficients and correction variables respectively which are set according to engine operating parameters to such values as optimize engine operating characteristics such as fuel consumption and engine accelerability the cpu 5b supplies driving signals based on the results thus calculated via the output circuit 5d to the fuel injection valves 6 fig2 shows a program for calculating the air fuel ratio correction coefficients r ko2 and l ko2 which are executed at predetermined fixed time intervals e g 5 msec at steps s1 to s8 it is determined whether or not first feedback control effecting conditions are satisfied under which the feedback control based on the outputs from the upstream o2 sensors 16r and 16l can be executed specifically it is determined whether or not the engine coolant temperature tw is higher than a first predetermined engine coolant temperature two2 e g 25 u00b0 c at the step s1 whether or not a flag fwot which is set to a value of 34 1 34 when the engine is in a predetermined high load operating condition is equal to a value of 34 0 34 at the step s2 whether or not.