Driving slow does not always = good FC. Even though you're using less fuel, you're covering even less distance.

yup the best way is use the instant fc indicatior.
u will found out u drive too slow your fc is too high, u drive to fast ur fc high too..
the best way is by checking the instant fc indicator and try to drive the best driving style fit to current traffic or road.

why not 

Fuelly is for tracking FC per tank or long term FC.

Instant FC readings tells you in real time if your driving is fuel efficient simply by showing you instantly increasing or decreasing FC figures.

Depends on car models, some are quite accurate.

But anyway, like I said it serves as an indication of how fuel efficient is your driving, the exact figures don't matter, the only things that matter is whether the figure is increasing or decreasing while you drive.

My Saga LMST (year 2007) has been sucking up the fuel like a thirsty bear recently. The problem came after the engine started to 'buat hal'. After switch off, the engine would not stop immediately, instead shake for few more seconds only stop. From then on, fuel consumption became very high, from 14km/L to 8km/L. Switched from Shell to Caltex, and sent the car to workshop, service and tuning auto choke, everything back to normal with slightly high rpm, and fuel consumption for the recent tank is 11.4km/L.

I have few concerns:
1) Is 11.4km/L consider ok? 90% city drive. I don't want to sound silly to go back to the workshop, though if the high rpm persist I might need to send back.
2) The fuel capacity for LMST is 45 L right? There's one time I refuel, the fuel insert until 45.12L but the gun didn't stop or anything! I suspect it's the gun's problem. That tank only lasted me 430km (before repair)

Thanks for the reply Ever since the first RM50 fuel couldn't last me til 300km I got paranoid and confused