I had Baleno 2004 Jxr in Ancient times. I also got the same problem. Please check the following.
a) The EFI jets are nneded to be Changed at 60000Km in Baleno. So plz go for it.
b) Secondly, In baleno if you dont keep the Petrol Tank upto minimum HALF, when u push the accelerator hard in initial gears it will immediately back off and u will feel a great puch back......
So do the needy ASAP.
Regds, (ALso if u have any other prob in baleno do contact me)