Salam, I am facing an issue with my 8th gen Honda civic automatic.
When my car reaches to normal running temperature it drops rpm below the idle rpm range (400-550 rpm) then suddenly comes back to normal idle rpm range 750-800 rpm. This happens when car is stopped on signal or when it is in Parking/neutral.
Also recently I've cleaned the intake manifold, changed spark plugs, spark coils and did general tuning after tuning got my throtel body recalibrated.
Could it be a sign of dirty fuel filter as my car has done 150000 km I am not sure if the previous owner ever changed the fuel filter.
What could be the possible reasons?
