GM Daewoo Kalos - Excessive fuel consumption 15L/100km

Hello, There are several causes for excessive fuel consumption . Dirty or clogged air filter, leaking gas hose or fuel lines, under inflated tires, wrong sized tires, excessive weight in the trunk, a heavy foot on the gas pedal are only a few.

Only the air filter would come into play, if you
have created vacuum leaks in the ducting & thru
unmetered air

Maybe unrelated issues you have there before

The upstream O2 Sensors could be replaced at
100,000 miles & you could look at fuel trim on a
road test

Need new spark plugs every 3 years

Clean the MAF Sensor

HI do you now the color of the smoke
if engine emits white smoke its not burning the fuel
it could be water mixing with fuel = head gasket even tho you
dot have water in the oil
if engine emits black smoke - that's excessive fuel to air ration
check air filter & air inlet to see if clogged
if engine emits blue smoke - excessive oil consumption
cloud be valve seals

That fuel consumption is a bit heavy, but not excessive, depending on the driving conditions. In heavy traffic and slow town driving with a lot of stop starts it would be acceptable but on the open road in 2 wheel mode it would be excessive. Kia do not seem to manage much better than about 8-10 l/100km, even on their sedans.

Sounds like the Oxygen sensor in the exhaust may not be working effectively. Check the connections and wiring running to it. The Oxygen sensor only starts to work when hot so be careful. The sensor outputs a pulse of voltage when the engine is running. If the voltage output is steady then it needs replacing.

possible temp sender unit, very common

check air mass.

this could be an air intake problem, check the air filter but what ive seen before is the flexible intake pipe collopse only when the engine was under pressure as you describe.Try removing this pipe & driving again but not for long as dust would enter the engine .it might confirm or elimiate this.

You're going to have to figure out what's causing the misfire. The car is almost 10 years old, so change the plugs to start with. If you still have a misfire, go to auto zone and have them pull the codes to find out which cylinder is the issue. Then figure out fuel or spark? Coil or injector? Was there a lean code? Check for a vacuum leak. Change the fuel filter and air filter for maintanence. The cruise control may be another issue.

Brakes could be binding or hand bake cable holding on but you think youd smell burning brakes if that was the case!What condition is the oxy sensor in ,maybe carboned up and contaminated which can tell the engine management to supply more fuel than required.is the air filter air box in good condition and air box lid securely fastened.Should be sealed from air box to throttle body If the air filter is clogged and dirty that can lead to excess fuel consumption.Have you installed any injector cleaner in the fuel tank.cleans up dirty injectors thst can cause excess fuel consumption.