Explosion sound in exhaust

Slm friends my vehicle is 207 1.4 petrol + LPG li. While the vehicle is at gasoline, it makes slight uneven work at idling and makes a loud noise in exhaust. I wonder why there is no problem in LPG.

most likely the fuel is coming too much because it can not burn the gasoline, it is jamming inside and detonating. I think the problem is simple. a problematic mechanism with lpg popeyes 2014-07-01 14:24:25

Why is it made from gasoline?