I would like to ask how much is the engine mounting in PJ??? Mind recommending some places which is cheap and reliable?

I changed mine satria 1.6 two mounting for >RM200 inclusive labor charge. with 1 drive shaft cover...

dremax,
it's a simple procedure requiring almost no advanced technical knowledge. assuming you wanna change all 4 engine mounts, you need to know how to remove 3 bolts from each mounting (based on wira/satria/putra, most cars should be the same) and going to the parts store to buy 4 new engine mounts. that's it.

other factors that could cause poor idling are a blocked/clogged PCV valve (Positive Crankcase Ventilation valve). cheap to replace, only RM28 for the hose and the valve, get it from local part stores cause ori proton ones cost RM70+ for the valve alone!