drastic rise in fuel consumpton
 

the problem started about a month and a half ago when i noticed my average fuel consumption went from about 8.3L/100km (28.3mpg) to 9.3L/100km (25.3mpg), my driving style and route hasn't changed since i own my car and i felt like this happened overnight.

i have 133k kms (83k miles) on my car and i've been following the regular maintenance schedule and have changed to synthetic oil since 100k kms, i also recently changed my spark plugs as well as flushed my coolant

one thing i did notice when this all started was irregularity on my rpm. if i were to stop the car quickly (clutch in), the rpm would drop to below the idle point and the car shakes a lil cause of the potential stall but it would never stall and goes back to the regular idle speed. that never happened to me before.

anyone has any thoughts or suggestions? i'm lost.

help!:crap: