Greetings to all Swift owners
I am a newbie and I would like to ask some questions.
I recently bought a 2nd hand Suzuki Swift 2008 1.5GLX ZC21. 100% stocks. The mileage is only 40,000KM. The previous owner just kept it in the garage. Everything is working fine and still tight like new car. Smooth engine and transmission. 2016 Yoko AE01 tyres but the thread still 95%. Tyres all pumped up to 240Kpa as per the recommendation. No engine warning light, no bad exhaust smell. I've given a full 40K major service with Shell Helix Ultra 5W/40, changed the air filter to original K&N.
I've been reading the spec for this model and all stated the AVG fuel economy (FE) at least 14-16 KM/L combine. However, my own FE is very poor. The car mostly used for ferrying kids to school nearby, up to 12km round trip with traffic light stop and go. The car can only manage to achieve 7.5KM/L. If I ever hit the highway, the total combined 1 full tank probably max only 9-10 KM/L.
I wonder what could have gone wrong? Any hidden faulty sensors? O2 sensors? clogged fuel injectors? Have any of the member here ever encounter the same issue? I've visited few workshops and they all saying "it's normal".
I know it's a 12 years old car but should not be that really old. At 7.5KM/L FE, I feel it drinks way too much for a 1.5L car. It's almost the same FE like a 90' old car.
Since I've never owned the car when it's still new, then I totally have no idea what is the real FE when the car was its showroom condition. I am hoping any of the senior and experience ZC21 swift owner can shed some light for me.
Thank you for your help and advise

Wah that is bad! FYI to put it into perspective, 7.5km/ltr is like my 400+hp 2005 Evo 9 driven smoothly. Lol My son's remapped Swift Sport ZC31S 1.6 manual with free flow modified loud exhaust can easily average 10km/ltr when driven like nuts! If driven smoothly, it'll reach real avg. 12-13km/ltr. Mileage already over 150k km.
You need to check the air fuel ratio if running too rich mixture. Try do some carbon cleaning first. Bring to a reputable Swift specialist. If you're in Klang Valley, I can recommend you go to Fineworks Garage Enterprise in Subang, they are very knowledgeable on Swifts and very meticulous too with their work. The boss owns a ZC21 AT too and plays with some Swift race cars.