Problem with my Hyundai Accent Car?

[docardlove1980]

I own a Hyundai Accent GLX Car Model 2001. After purchasing the car I got fitted LPG kit in the same and the car was running fine both on Petrol and LPG. Since few days I am facing undermentioned problems:
1. The car does not run smoothly on Petrol and did not take pick-up.
2. When the car run on LPG the pick up is very fine but the same Break Air Filter with a Blast like sound. I have replaced Air Filter Assembly twice.
3. The local mechanics are not finding ways to resolve the problem. In the authorised show room of Hyundai Accent LPG problem is not being resolved.
Please advice me the reasons of the same and probable resolution to my problem

thanks