2002 Other Daewoo Models performance query

We have had the car for 6 months, it has always been serviced. But it burns alot of oil - needs to be topped up every month or so depending on mileage, or becomes tappy - it is not leaking oil.
Also the engine is very 'farty' and has problems especially in 4th gear up hill.
The braking is also questionable, causing a shaking sensation through the steering wheel when braking gently from high speed. When brakes are applied firmly, this does not happen. The car does not pull on braking, and the hubs are not hot to the touch after driving.
any ideas on what could be the cause of both would be gratefully received.
many thanks.