annoying problem for 02 polo 1.2s 65 12v, low mpg ... please help.... thx

[30miles]

i have a 02 reg 1.2s 65 12v polo. milage is 18600. recently my car only can do 25mpg. normally should be the 34 mpg in town which says on the manual book.
i did a lot of short distance driving recently and i do not keep heavy stuff on board.
is this caused by the spark plugs? i have not replaced them in the last service, which i carried out for my car in the last week.
please please some one could give me some idea about what is going on? thank you very much...

[adamss24]

Have someone check the car with diagnostic equipment. I suspect a faulty lambda sensor (a bit early though) or faulty/blocked fuel injectors or could be a faulty MAF...Post the fault codes on the forum. Does it runs lumpy at iddle and does it smell like unburnt fuel when you stay behind the car while someone its revving the engine, also is the car running poor overall, i mean does it lacks power ? Good luck.

[30miles]

Have someone check the car with diagnostic equipment. I suspect a faulty lambda sensor (a bit early though) or faulty/blocked fuel injectors or could be a faulty MAF...Post the fault codes on the forum. Does it runs lumpy at iddle and does it smell like unburnt fuel when you stay behind the car while someone its revving the engine, also is the car running poor overall, i mean does it lacks power ? Good luck.

many thanks for the reply... the lambda warning light never shows there is a problem, but i will get it checked right away. and i dont think there is a lack of power when i drive the car. i will go and smell it tomorrow first thing. thanks again.