Pajero 99 3.5 emmision problem

I own Pajero 99 3.5 SWB recently I had this problem of petrol smell comming out of the exhaust I have replaced the 3 ingnition coils, plugs and cables and the problem still exisits, and also the engine is unstable especially when A/C is turned on, please is there any one that knows what might the problem be?