1998 suzuki swift it has 39000 km runs good it gets 450 km to the tank

First,take a look at the spark plugs.Are they a light brown?If they are the fuel mixture is good.Check timing,lighten the vehicle from excess weight carried,check for dragging brakes and alignment that is out of spec,tire pressure and drive gently at the speed limit,not over.Also use fuel with NO ETHANOL if you can find it.Ethanol drops fuel economy quiet a bit.

you are posted to a USA forum so answers on Cino are limited.
Cino smacks of Australia. join a suzuki forum there? and win?

what country, the book varies by country and engines.
some countries dont have your engine ,so is skipped.
Free now that is a tall order, and your time on google , is not going to be my time.... not ever.

we have 4 major on line virtrual FSM, an tnot one covers cino.

why not stated real year, not a range?

https://suzukipitstopplus.com/Products/1123-1998-swift-service-manual.aspx

here is OUR swift, and will not be correct for yours.

short in harness check all wires with meter

Average is 30 mpg ,
Toyota Prius - 50 mpg.
I think you doing pretty good.

If you can't find one over there check out faxonautoliterature. They carry original manufacturer service manuals and they list 3 different ones for your car. I have used them before and found their service to be excellent. They are in California and I live in Eastern Canada and can get manuals in about 7-8 days. Hope this helps.

get the radiator checked and get the air filter cleaned and get the check teh coolant level. i ahd same issue in my swift. and it got fixed. just follow these.. it will fix the problem. no big issue.

Can you describe what the car does when it is hot? Mike. Rate 100% and respond back please.

evap purge valve is stuck closed you need a new one

look on top of the tank .Do not remove tank just lower it.

Jan

hi
im dave
Is there a leak in one of the fuel lines? Check the length of the fuel lines from the pump (you may need an extendable mirror to see the top of gas tank) right up to the point where it enters the fuel rail on the engine. Take special note of the junctions and try to do it with the car running and at a slight idle so fuel is pumping. Check next for a smell of too much gasoline along the fuel rail as one of the injectors may be improperly seated and or broken and leaking. Has the service engine check engine light come on at all or come on and gone out. If your o2 sensor(s) go you use more fuel. If they go there should be a code stored in your PCM (computer). You can pull any codes out of that car by finding the connector and jumping it. Also if your air element(filter) or any pipes are clogged in that system up to the throttle body you will use much more fuel.

Let me know how these tests go