Bad average corolla 11th gen prefacelift

[nitricacid49]

My corolla 1.3 manual giving an average of 11.6 even on long routes and as it is cold we are not using ac.I had the engine tuned last month and the oil changed recently
Prior to tune it gave 14.5 -15 per litre with ac
How can I improve the avg?
Kindly help

[nitricacid49]

Also it has slow throttle response. If given won't rev instantly but when revs even I am finished throttling the rpm would go higher for an instant

[aziz.rehan]

Which oil did u put in also grade?

[aziz.rehan]

Change spark plugs and clean throttle body

[nitricacid49]

Brother this was written on the chit Zickx520w20 37