The way you guided on Throttle Sensor beneath the pedal n etc i had a feeling that there is something in my brother, but......................
Khair, tons of things effect your mileage, i am not going to talk about tire pressures and driving ethics.
1: Check plug wires if they allow the resistance to pass, you are good to go
Get a simple multimeter or volt meter, attach one end of the voltemter wire to one end of plug wire, and other with the other, if meter shows reading / or needle moves to the end, THINGS ARE VOILA !!!
2: Most importantly, check air intake manifold / air cleaner. Typically EFI engine is designed to maintain an air fuel mixture with the ratio of 14:1. If Air intake is not working well it will move uptp 13:2, 12:3, 11:4 etc. means more fuel and less air.
OBD Scan for Short / Long Term Fuel Trims either by HiScan or whatsoever.
3: Get you O2 Sensor checked, If the Oxygen sensor is not working good, it may keep bothering ECU to pump more fuel then air
Here again with OBD Scan Tool
4: Check you Throttle Body is clean?
5: Check Fuel Injectors?
To best shot, get a Carbon Cleaner and clean the throttle body plus get any budget suiting PETROL Based Fuel Injector Cleaner, to my experience "Liqui Moly" or "Mothercare" is the best.
On the canister, you will get the usage instructions, simply the best way is doing some maths with the prescribed value and adding it directly into the full tank of petrol i.e. 35 Liter. As you will drive, it will keep cleaning the injectors.
Ref: Short Term Long Term Fuel Trim Explained