I have a Honday City 2015 Aspire Prosmatic. Driven 115km so far. I brought it 1.5years ago and since then I never took my car for any tuning, just doing oil change since then. The car is still in perfect condition but the mileage went down over the time from 14.5km/l to 13.3km/l. Please suggest if tunning is needed or not. I am using Honda 10w30 for engine oil but someone suggested that now i should use 10w40 instead. Guidance needed!!
